A flavorful compound produced during the fermentation process when the yeast digests sugars. At higher concentrations, it may affect a beer’s flavor. At low-concentration rates, it can taste like green apples; at high concentration – latex paint.

Acid Cleaner

Although several blends of acid cleaners are recommended to assist in beer stone and water stone removal, some acids react with system components. Phosphoric acid-based blends are the only ones safe on all materials.


Acrospire is the sprout of a grain seed, the beginning of a new plant. As the acrospire grows, enzymes in the grain become active, too, which breaks down nutrients so that they can be readily absorbed by the emerging plant.


Any unmalted grain or other fermentable ingredient used in the brewing process. Adjuncts used are typically either rice or corn, and can also include honey, syrups, and numerous other sources of fermentable carbohydrates. They are common in mass produced light American lager-style beers.


The action of introducing air or oxygen to the wort (unfermented beer) at various stages of the brewing process. Proper aeration before primary fermentation is vital to yeast health and vigorous fermentation. Aeration after fermentation is complete can result in beer off-flavors, including cardboard or paper aromas due to oxidation.


AHA (American Homebrewers Association) was founded in 1978 and advocates for hombrewers rights, publishes Zymurgy Magazine, is a division of the Brewers Association and hosts the world’s largest beer competition.


A synonym for ethyl alcohol or ethanol, the colorless primary alcohol constituent of beer. Alcohol ranges for beer vary from less than 3.2% to greater than 14% ABV. However, the majority of craft beer styles average around 5.9% ABV.

Alcohol by Volume (ABV)

A measurement of the alcohol content of a solution in terms of the percentage volume of alcohol per volume of beer. This measurement is always higher than Alcohol by Weight. To calculate the approximate volumetric alcohol content, subtract the final gravity from the original gravity and divide by 0.0075. For example: 1.050 – 1.012 = 0.038/0.0075 = 5% ABV.

Alcohol by Weight (ABW)

A measurement of the alcohol content of a solution in terms of the percentage weight of alcohol per volume of beer. For example: 3.2 percent alcohol by weight equals 3.2 grams of alcohol per 100 centiliters of beer. This measure is always lower than Alcohol by Volume. To calculate the approximate alcohol content by weight, subtract the final gravity from the original gravity and divide by 0.0095. For example: 1.050 – 1.012 = 0.038/0.0095 = 4% ABW.


  1. Warming taste of ethanol and higher alcohols. Can be described as spicy and vinous in character. The higher the ABV of a beer, often the larger the mouthfeel it has. Alcohol can be perceived in aroma, flavor and as a sensation.
  2. A person with a disabling disorder characterized by compulsive uncontrolled consumption of alcoholic beverages.


Ales are beers fermented with top fermenting yeast. Ales typically are fermented at warmer temperatures than lagers, and are often served warmer. The term ale is sometimes incorrectly associated with alcoholic strength.

All Extract Beer

A beer made with malt extract as opposed to one made from barley malt or from a combination of malt extract and barley malt.

All-Grain Beer

A beer made with malted barley as opposed to one made from malt extract or from malt extract and malted barley.

All-Malt Beer

A beer made entirely from mashed barley malt and without the addition of adjuncts, sugars or additional fermentables.

Alpha Acid

One of two primary naturally occurring soft resins in hops (the other is Beta Acid). Alpha acids are converted during wort boiling to iso-alpha acids, which cause the majority of beer bitterness. During aging, alpha acids can oxidize (chemical change) and lessen in bitterness.

Alpha and Beta Amylase

Important enzymes in brewing beer and liquor made from sugars derived from starch. Different temperatures optimize the activity of alpha or beta amylase, resulting in different mixtures of fermentable and unfermentable sugars.

Apparent Attenuation

A simple measure of the extent of fermentation that wort has undergone in the process of becoming beer. Using gravity units (GU), Balling (B), or Plato (P) units to express gravity, apparent attenuation is equal to the original gravity minus the final gravity divided by the original gravity. The result is expressed as a percentage and equals 65% to 80% for most beers.

Aromatic Hops

Refers to hop additions that take place later in the boiling process. Shorter amount of time spent in the boil kettle will provide more aromatic characteristics from the hops rather than bittering characteristics.


A characteristic of beer taste mostly caused by tannins, oxidized (phenols), and various aldehydes (in stale beer). Astringency can cause the mouth to pucker and is often perceived as dryness.


The reduction in wort specific gravity caused by the yeast consuming wort sugars and converting them into alcohol and carbon dioxide gas through fermentation.


A process in which excess yeast cells feed on each other producing a rubbery or vegetal aroma.



A measure of the density of wort or beer. Degrees balling (or °Plato) corresponds to the percentage of sugar in water and is used to measure the extract in wort or in beer. Ballings may be determined by a hydrometer – or balling spindle – which floats in the liquid at a level corresponding to sugar content (See also hydrometer), by a refractometer where a beam of light is deflected in direct proportion to the amount of sugar or by numerous methods of modern instrumentation that measure density.


The feature of a beer concerned with the balance of various flavors, aromas, tastes and sensations.


The oldest and most predominant ingredient in brewing is barley....

A cereal grain derived from the annual grass Hordeum vulgare. Barley is used as a base malt in the production of beer and certain distilled spirits, as well as a food supply for humans and animals.


Brewing barrels

A standard measure in the U.S. that is 31.5 gallons. A wooden vessel that is used to age/condition/ferment beer. Some brewer’s barrels are brand new and others have been used previously to store wine or spirits.

Beer Stone

Grayish-brown deposit formed from calcium and fermentation byproducts on the surface of equipment in prolonged contact with beer.

Beta Acids

One of two primary naturally occurring soft resins in hops (the other is Alpha Acid). Beta acid contributes very little to the bitterness of beer and accounts for some of its preservative quality.


A diastatic enzyme produced by malting barley to convert dextrins and soluble starches into fermentable sugars.


A small vessel traditionally used to measure the amount of yeast to be proportioned into the wort for the proper pitching rate.

Bittering Hops


Refers to hop additions that take place early in the boiling stage of the brewing process. The longer hops are boiled, the more bittering characteristics will come from those hops.


In beer, the bitterness is caused by the tannins and iso-humulones of hops. Bitterness of hops is perceived in the taste. The amount of bitterness in a beer is one of the defining characteristics of a beer style.

Bitterness Units (BU)

Same as International Bitterness Units (IBU).

BJCP (Beer Judge Certification Program)

BJCP (Beer Judge Certification Program) is a non-profit organization formed in 1985 to promote beer literacy and the appreciation of real beer, and to recognize beer tasting and evaluation skills.


The mixing together of different batches of beer to create a final product.


The consistency, thickness and mouth-filling property of a beer. The sensation of palate fullness in the mouth ranges from thin to full-bodied.


A critical step during the brewing process during which wort (unfermented beer) is boiled inside the brew kettle. During the boiling, one or more hop additions can occur to achieve bittering, hop flavor and hop aroma in the finished beer. Boiling also results in the removal of several volatile compounds from wort, especially dimethyl sulfide (see below) and the coagulation of excess or unwanted proteins in the wort (see “hot break“). Boiling also sterilizes a beer as well as ends enzymatic conversion of proteins to sugars.


A 22-ounce bottle of beer.

Bottle Conditioning

A process by which beer is naturally carbonated in the bottle as a result of fermentation of additional wort or sugar intentionally added during packaging.

Bottom Fermentation

One of the two basic fermentation methods characterized by the tendency of yeast cells to sink to the bottom of the fermentation vessel. Lager yeast is considered to be bottom fermenting compared to ale yeast that is top fermenting. Beers brewed in this fashion are commonly called lagers or bottom-fermented beers.


White Labs WLP640 Brettanomyces Anomalus

A type of yeast and more specifically a genus of single-celled yeasts that ferment sugar and are important to the beer and wine industries due to the sensory flavors they produce. Brettanomyces, or “Brett” colloquially, can cause acidity and other sensory notes often perceived as leather, barnyard, horse blanket and just plain funk. These characteristics can be desirable or undesirable. It is common and desirable in styles such as Lambic, Oud Bruin, several similarly acidic American-derived styles, and many barrel-aged styles.

Brew Kettle

Brewing Process (brew kettle)

One of the vessels used in the brewing process in which the wort (unfermented beer) is boiled

Brewers Association

The Brewers Association is an organization of brewers, for brewers and by brewers. More than 2,300 U.S. brewery members and 43,000 members of the American Homebrewers Association are joined by members of the allied trade, beer wholesalers, retailers, individuals, other associate members and the Brewers Association staff to make up the Brewers Association.


A restaurant-brewery that sells 25% or more of its beer on site. The beer is brewed primarily for sale in the restaurant and bar. The beer is often dispensed directly from the brewery’s storage tanks. Where allowed by law, brewpubs often sell beer “to-go” and /or distribute to off site accounts.


A sealing stopper, usually a cylindroconical shaped piece of wood or plastic, fitted into the mouth of a cask or older style kegs such as Hoff-Stevens or Golden Gate.

Bung Hole

The round hole in the side of a cask or older style keg, through which the vessel is filled with beer and then sealed with a bung.

Burton Snatch

The aroma of Sulphur indicating the presence of sulphate ions.


Desirable and undesirable compounds that are a result of fermentation, mashing, and boiling.


Calcium Carbonate

A mineral common in water of different origins. Also known as chalk, sometimes added during brewing to increase calcium and carbonate content.

Calcium Sulfate

A mineral common in water of different origins. Also known as gypsum, sometimes added during brewing to increase calcium and sulfate content.  


A group of organic compounds including sugars and starches, many of which are suitable as food for yeast and bacteria.

Carbon Dioxide

The gaseous by-product of yeast. Carbon dioxide is what gives beer its carbonation (bubbles).


The process of introducing carbon dioxide into a liquid (such as beer) by: …pressurizing a fermentation vessel to capture naturally produced carbon dioxide; …injecting the finished beer with carbon dioxide; …adding young fermenting beer to finished beer for a renewed fermentation (kraeusening); …priming (adding sugar to) fermented wort prior to packaging, creating a secondary fermentation in the bottle, also known as “bottle conditioning.”


A large glass, plastic or earthenware bottle.


One of the essential oils made in the flowering cone of the hops plant Humulus lupulus.


A barrel-shaped container for holding beer. Originally made of iron-hooped wooden staves, now most widely available in stainless steel and aluminum.

Cask Conditioning

Storing unpasteurized, unfiltered beer for several days in cool cellars of about 48-56°F (13°C) while conditioning is completed and carbonation builds.

Caustic Soda, or NaOH (Sodium Hydroxide)

A high pH chemical commonly used in blending draught line cleaning solutions that will react with organic deposits in the draught beer line. Very effective, but also very dangerous. Commonly used in oven cleaners.


Storing or aging beer at a controlled temperature to allow maturing.

Chill Haze

Hazy or cloudy appearance caused when the proteins and tannins naturally found in finished beer combine upon chilling into particles large enough to reflect light or become visible.


Cider refers to unfermented apple juice in the US but to fermented apple juice in the rest of the world. In the US, fermented apple juice is called hard cider.

Closed Fermentation

Fermentation under closed, anaerobic conditions to minimize risk of contamination and oxidation.

Coil Box

A coil box (also known as a jockey box) is a cooling system consisting of a coil of stainless steel immersed in ice water that brings beer down to serving temperature at the point of dispense. It is often used at picnics and special events where normal keg temperature cannot be maintained.

Cold Break

The flocculation of proteins and tannins during wort cooling.


The hue or shade of a beer, primarily derived from grains, sometimes derived from fruit or other ingredients in beer. Beer styles made with caramelized, toasted or roasted malts or grains will exhibit increasingly darker colors. The color of a beer may often, but not always, allow the consumer to anticipate how a beer might taste. It’s important to note that beer color does not equate to alcohol level, mouthfeel or calories in beer.


A step in the brewing process in which beer is matured or aged after initial fermentation to prevent the formation of unwanted flavors and compounds.

Contract Brewing Company

A business that hires another brewery to produce some or all of its beer. The contract brewing company handles marketing, sales and distribution of its beer, while generally leaving the brewing and packaging to its producer-brewery.


Coolship at Anchor Brewing Co.

A coolship is a type of brewing vessel traditionally used in the production of beer. It is a broad, open-top, flat vessel in which wort cools. The high surface-to-mass ratio allows for more efficient cooling. Contemporary usage includes any open fermentor used in the production of beer, even when using modern mechanical cooling techniques.  Coolships are still used in traditional lambic brewing, where the wort is cooled and airborne yeasts and bacteria present in the brewery are allowed to inoculate the beer naturally, in order to create a spontaneous fermentation.


A coupler is a device that is attached to the top of a keg to connect the gas line and the beer line to the keg. It opens the valve in the keg to allow gas in through the gas line and push beer out through the beer line. There are several different coupler styles available for use with the different styles of keg valves. Most domestic U.S. brewing companies use the “D” system keg coupler.

Craft Brewery

According to the Brewers Association, an American craft brewer is small, independent and traditional. Small: Annual production of 6 million barrels of beer or less (approximately 3 percent of U.S. annual sales). Beer production is attributed to the rules of alternating proprietorships. See Independent, and Traditional


A crowler is, essentially, a growler in a can. It’s a 32-ounce aluminum vessel meant to keep your favorite beers fresh until you decide to drink it. It opens the same way you’d crack open a regular beer can. The filling process for the crowler improves upon the growler in that it removes all oxygen from the container. Filling a crowler is a more technical process than filling a growler. First, the bartender takes the can and ensures it is sanitized and purged of all air. Oxygen will degrade the beer if it’s present, and by removing it, they’re helping the brew maintain optimal freshness. They then fill the crowler with your selection and use a machine to apply a lid and pressure-lock it onto the can. Once it’s locked, it’s ready to take home.


Cuvee is a large vat used for fermentation.


Decoction Mash

A method of mashing that raises the temperature of the mash by removing a portion, boiling it, and returning it to the mash tun. Often used multiple times in certain mash programs.

Degrees Plato

An empirically derived hydrometer scale to measure density of beer wort in terms of percentage of extract by weight.


An insulated, pressurized container for liquefied gas such as CO2.


A group of complex, unfermentable and tasteless carbohydrates produced by the partial hydrolysis of starch, that contributes to the gravity and body of beer. Some dextrins remain undissolved in the finished beer, giving it a malty sweetness.

Dextrose (or glucose)

A monosaccharide used to prime bottle-conditions beers.


A volatile compound produced by some yeasts which imparts a caramel, nutty or butterscotch flavor to beer. This compound is acceptable at low levels in several traditional beer styles, including: English and Scottish Ales, Czech Pilsners and German Oktoberfest. However, it is often an unwanted or accidental off-flavor.


Refers to the diastatic enzymes that are created as the grain sprouts. These convert starches to sugars, which yeast eat.

Dimethyl Sulfide (DMS)

At low levels, DMS can impart a favorable sweet aroma in beer. At higher levels DMS can impart a characteristic aroma and taste of cooked vegetables, such as cooked corn or celery. Low levels are acceptable in and characteristic of some Lager beer styles.

Direct Draw

A draught beer system with self-contained keg storage and a dispense setup that connects the keg to the faucet using a short jumper connection. This type of dispense system is generally air-cooled and dispenses beer through lines five feet long or shorter.


A process in which brewers add sugar and/or yeast to promote secondary fermentation. Can be added to the cask or bottle.

Doughing in (or mashing in)

Mixing ground malt with water, the first step in all-grain brewing.

Draught Beer

Beer drawn from kegs, casks or serving tanks rather than from cans, bottles or other packages. Beer consumed from a growler relatively soon after filling is also sometimes considered draught beer.

Dried Malt Extract (DME)

A malt extract in a dried powder form (often called DME). Becomes very sticky and will clump when exposed to humidity. Store unused DME in a tight sealed, cool & dry environment.

Drum Kiln

A cylindrical kiln used to produce malts of myriad colors and properties without the application of direct heat.

Dry Hopping

The addition of hops late in the brewing process to increase the hop aroma of a finished beer without significantly affecting its bitterness. Dry hops may be added to the wort in the kettle, whirlpool, hop back, or added to beer during primary or secondary fermentation or even later in the process.

Dry Kit

A homebrewing kit that contains dry malt extract, hops, and sometimes specialty malts.

Dual Purpose Hops

Hops that are added to provide both bittering and aromatic properties.


EBC (European Brewing Convention)

EBC is an organization representing the technical and scientific interests of the brewing sector in Europe. The EBC defines itself as the scientific and technological arm of The Brewers of Europe. Among brewers, EBC is perhaps best known for the EBC units measuring beer and wort colour, as well as EBC units for quantifying turbidity (also known as haze) in beer.


The bubbling in beer primarily caused by dissolved carbon dioxide gas.


The starch-containing sac of the barley grain. The endosperm constitutes 80 to 85 percent of the dry weight of the grain. Part of this starch serves as a food reserve for the growing embryo, while the remainder constitutes the bulk of the extract during mashing.


Naturally occurring, complex compounds. When in solution, enzymes produce chemical changes in other compounds without resulting in changes to the enzyme itself. Enzymes are sensitive to heat and undergo deactivation at about 112 to 140 degrees Fahrenheit.

Essential Hop Oils

Essential hop oils are what is isomerized in wort and provide the aromatic and flavor compounds that are associated with hop additions.


Volatile flavor compounds that form through the interaction of organic acids with alcohols during fermentation and contribute to the fruity aroma and flavor of beer. Esters are very common in ales.


Also known as ethyl alcohol, one of many compounds classified as alcohol, but synonymous with the common definition of alcohol as contained in beer.

European Bittering Units

See International Bittering Units.


Any beer produced for the express purpose of exportation. For example: export-style German lagers or export-style Irish stouts.

Extract Brewing

Making beer from malt extract syrup or powder as opposed to unprocessed malt (which is used in all-grain brewing).



One of the essential oils made in the flowering cone of the hops plant Humulus lupulus.

Fermentable Sugars

Sugars that can be consumed by yeast cells which in turn will produce ethanol alcohol and c02.


The chemical conversion of fermentable sugars into approximately equal parts of ethyl alcohol and carbon dioxide gas, through the action of yeast. The two basic methods of fermentation in brewing are top fermentation, which produces ales, and bottom fermentation, which produces lagers.

Fermentation Lock

A one-way valve, often made of glass or plastic that is fitted onto a fermenter and allows carbon dioxide gas to escape from the fermenter while excluding ambient wild yeasts, bacteria and contaminants.


The passage of a liquid through a permeable or porous substance to remove solid matter in suspension, often yeast.

Final Gravity

The specific gravity of a beer as measured when fermentation is complete (when all desired fermentable sugars have been converted to alcohol and carbon dioxide gas). Synonym: Final specific gravity; final SG; finishing gravity; terminal gravity.


The process of adding clarifying agents such as isinglass, gelatin, silica gel, or Polyvinyl Polypyrrolidone (PVPP) to beer during secondary fermentation to hasten the precipitation of suspended matter, such as yeast, proteins or tannins.


The behavior of suspended particles in wort or beer that tend to clump together in large masses and settle out. During brewing, protein and tannin particles will flocculate out of the kettle, coolship or fermenter during hot or cold break. During and at the end of fermentation, yeast cells will flocculate to varying degrees depending on the yeast strain, thereby affecting fermentation as well as filtration of the resulting beer.

Forced Carbonation

The beer is place into a sealed (or soon to be sealed) container and carbonation is rapidly added. Under high pressure, the CO2 is absorbed into the beer.

Fresh Hopping

The addition of freshly harvested hops that have not yet been dried to different stages of the brewing process. Fresh hopping adds unique flavors and aromas to beer that are not normally found when using hops that have been dried and processed per usual. Synonymous with wet hopping.

Fusel Alcohol

A family of high molecular weight alcohols, which result from excessively high fermentation temperatures. Fusel alcohols can impart harsh or solvent-like characteristics commonly described as lacquer or paint thinner. It can contribute to hangovers.



Gallon is a measure of liquid volume. One U.S. gallon equals 3.785 liters and one imperial gallon is 4.546 liters.


Gelatin is a colorless, tasteless protein used by brewers for fining. Gelatin is a protein obtained by boiling skin, tendons, ligaments, and/or bones with water. It is usually obtained from cows or pigs.


Growth of a barley grain as it produces a rootlet and acrospire.

Glycol or Propylene Glycol

Glycol or Propylene Glycol is a food-grade refrigerant that is recirculated through insulated tubing bundles to keep beer cold.


Tasting or smelling like cereal or raw grains.


Ground malt and grains ready for mashing.


A jug- or pail-like container once used to carry draught beer bought by the measure at the local tavern. Growlers are usually ½ gal (64 oz) or 2L (68 oz) in volume and made of glass. Brewpubs often serve growlers to sell beer to-go. Often a customer will pay a deposit on the growler but can bring it back again and again for a refill. Growlers to-go are not legal in all U.S. states.


An old-fashioned herb mixture used for bittering and flavoring beer, popular before the extensive use of hops. Gruit or grut ale may also refer to the beverage produced using gruit.


Calcium sulfate, a naturally occurring calcium compound found in the earth and mined for a variety of uses. Often used in brewing to increase calcium in water for yeast nutrition and for increased beer stability.


Hand Pump

A device for dispensing cask conditioned draught beer using a pump operated by hand. The use of a hand pump allows the draught beer to be served without the use of pressurized carbon dioxide.

Head Retention

The foam stability of a beer as measured, in seconds, by time required for a 1-inch foam collar to collapse.

Heat Exchangers

Used to cool hot wort before fermentation.


The art of making beer at home. In the U.S., homebrewing was legalized by President Carter on February 1, 1979, through a bill introduced by California Senator Alan Cranston. The Cranston Bill allows a single person to brew up to 100 gallons of beer annually for personal enjoyment and up to 200 gallons in a household of two persons or more of legal drinking age.


A hopback is a sieve-like vessel that is filled with hops to act as a filter for removing the break material from the finished wort. Also known as a hop jack.


The addition of hops to unfermented wort or fermented beer. See Dry Hopping or Wet Hopping for additional details.

Hot Break

The flocculation of proteins and tannins during wort boiling.


Synonym for alpha acid, one of the two major resins found in hops. It is composed of humulone, cohumulone and adhumulone.


The dry outer layer of certain cereal seeds.    


Hydrometer used to measure the specific gra

A glass instrument used to measure the specific gravity of liquids as compared to water, consisting of a graduated stem resting on a weighted float.


Ice Beer

Beer produced by freeze concentration where ice crystals are removed after freezing leaving a stronger beer. Protein is also precipitated by the process which produces a more stable beer with lower flavor.

Immersion Chiller

A wort chiller most commonly made of copper that is used by submerging into hot wort before fermentation as a method of cooling.

Immersion Heater

A heating device used to maintain a constant temperature in the mash tun.

Immobilized Yeast

Yeast attached to support materials within fermenters reactors. This yeast mostly remains in place during fermentation and allows a clearer beer to be produced. It is also more active in its metabolism but is mostly used to mature beer rather than primary fermentation.

Imperial Gallon

An imperial gallon is 4.54 liters or 1.2 U.S. gallons.

Infusion Mashing

A traditional mashing process involving keeping the mash at a single temperature during the mash period. This is typically between 600 and 700C where amylase activity is maximal. Infusion mashes are usually employed for UK beers produced using well modified malt which has incurred extensive protein and b glucan digestion during malting.


The introduction of a microbe such as yeast or microorganisms such as lactobacillus into surroundings capable of supporting its growth.

International Bitterness Units (IBU)

The measure of the bittering substances in beer (analytically assessed as milligrams of isomerized alpha acid per liter of beer, in ppm). This measurement depends on the style of beer. Light lagers typically have an IBU rating between 5-10 while big, bitter India Pale Ales can often have an IBU rating between 50 and 70.

Invert Sugar

A mixture of fructose and glucose produced by chemically breaking down sucrose; used for boosting gravity and priming.

Iodine Test

In brewing this test is generally used to check on the degradation of starch to dextrins and malt sugar. Iodine turns from a yellow to dark blue, purple or red with various starches and dextrins, but not with sugars.


An ion that causes haze and oxidation and hinders yeast.


Isinglass, Caskleer or Magicol

A collagen extract from sturgeon and other fish swim bladders and used as a fining aid to settle yeast in conditioning of beer and in cask conditioned beer. The natural extract is hydrolysed by acid to release particles of highly positively charged collagen proteins which bind strongly to negatively charged yeast cells. Clarification is also enhanced by the production of a dense mesh work of fibers and cells which settles rapidly under gravity.

Iso-electric Point

A pH value at which the electrical charge of an amino acid is zero.

Isohumulones / Iso-alpha

Isohumulones are chemical compounds that contribute to the bitter taste of beer and are in the class of compounds known as iso-alpha acids that are found in hops.


Jetting Machine

An automatic machine used to wash bottles.

Jockey Box

A beverage-dispensing system, often used to serve beer, consisting of a picnic cooler with an internal cooling coil and one or more externally mounted taps. The cooler is filled with ice, and the beverage is chilled as it passes through the coil to the tap.



A straight sided pressure container for beer dispense. Kegs have a single entry valve with a central tube for exit of the beer and a surrounding collar for entry of pressurized gas to push the beer out. Application of the correct pressure for dispense is important as higher levels can result in gas being absorbed by the beer and fobbing on dispense. Most keg beer is brewery conditioned and stabilized by filtration and/or pasteurization.


An inert material used to enhance filtration of beer by producing a finely porous cake on a filter membrane. This cake increases in depth as beer is progressively filtered and particles remain entrapped in the cake allowing clear beer to filter through. Keiselguhr is made from the shells of diatoms but other filter aids may be composed of clay or silica hydrogel.


The whole grain or seed of a cereal or the inner portion of a seed.


The process of heat-drying malted barley in a kiln to stop germination and to produce a dry, easily milled malt from which the brittle rootlets are easily removed. Kilning also removes the raw flavor (or green-malt flavor) associated with germinating barley, and new aromas, flavors, and colors develop according to the intensity and duration of the kilning process.

Krausen Wort

Krausen wort. Brewers sometimes add a little sweet unfermented wort to finished beer. This krausen wort causes natural carbonation.


Krausening occurs when producers add a little partly fermented wort to a brew during lagering. This causes a secondary fermentation and effervescence.



The lacelike pattern of foam sticking to the sides of a glass of beer once it has been partly or totally emptied. Synonym: Belgian lace

Lactic Acid

A common acid produced by a variety of yeasts and bacteria. A major spoilage flavor resulting from the growth of lactic acid bacteria in beer and detectable by a yogurt like aroma and taste. Lactic acid bacteria also produce distinctive flavors along with lactic acid, for example the butterscotch flavor diacetyl.


One of the predominant groups of lactic acid bacteria. A number of species including L. brevis, L. delbrueckii and L. pastorianus are contaminants of beer producing lactic acid and other off flavours. Lactic acid bacteria are commonly used in other food fermentations such as yoghurt and sauerkraut.


A rather general term for bottom fermented beers although traditionally used to designate beers matured for long periods at cold temperature. Lager beers today are generally very light in color, have some dimethyl sulphide aroma and are hoppy and moderately bitter in taste. They are filtered and brewery conditioned to produce a high carbonation and served from kegs through a faucet.


To age or store bottom-fermented beer in cold cellars at near-freezing temperatures for periods of time ranging from a few weeks to years, during which time the yeast cells and proteins settle out and the beer improves in taste. Lager in German means storage.

Large Brewery

As defined by the Brewers Association: A brewery with an annual beer production of over 6,000,000 barrels.

Lauter Tun

A separating vessel used to sparge a mash and separate clear wort from the residual grains. Differs from a mash tun in being wider with a larger floor area to give a faster run off. Lauter tuns also have stirring rakes to agitate the mash and may be used after the mash has been incubated in a cereal cooker with adjuncts. In this arrangements more mashings may be performed per day so increasing efficiency.


The process of separating the sweet wort (pre-boil) from the spent grains in a lauter tun or with other straining apparatus.


Removal of dissolvable matter from its mixture with an insoluble solid; major part occurring during mashing


Lees are the deposit of yeast and sediments at the bottom of a tank after fermentation.

Light Beer

Light beer is reduced-calorie beer. Producers create it by removing dextrine, a tasteless carbohydrate. Although beer, wine and spirits all contain calories, their consumption does not appear to increase weight!

Lightstruck (Skunked)

Appears in both the aroma and flavor in beer and is caused by exposure of beer in light colored bottles or beer in a glass to ultra-violet or fluorescent light.


Any of a class of enzymes that accelerate the hydrolysis of fats to fatty acids and glycerol.


Brewing terminology for water used in brewing. Supply liquor is obtained from local boreholes or direct from water company supplies. Brewing liquor is that used in the process whilst process liquors are used for washing, heating or other activities. The total amount of liquor used in brewing may be between 4 and 10 times the volume of beer produced. Reducing this volume is a major target of increasing efficiency of production and minimizing environmental impact.

Liter / Litre

Liter is a measure of volume equal to 33.8 ounces. Litre (British and Commonwealth spelling)


A scale used to measure color in grains and sometimes in beer. See also Standard Reference Method.

Low Alcohol Beer

A beer produced from a low gravity wort and incompletely fermented or from a higher alcohol fermentation but with the alcohol removed by evaporation. Generally brewed for a specific market low alcohol beers lack the complex character of standard beers and are often supplemented with malt and hop extracts to provide additional flavor.


The bitter resins found in the lupulin glands of hops, also knows as beta acids. There are three forms of lupulone: co-lupulone, lupulone and adlupulone.



  1. A 1.5L bottle.
  2. A German variety of hops (also grown in the US) and daughter of Galena. It is a high alpha cultivar and is often used for the base bittering.


A major brewing ingredient providing sugars for yeast fermentation. Usually derived from barley although other grains such as wheat, oats and rye may also be malted. Malted grains are softened by enzyme action during malting producing a modified grain. This softening results from digestion of cell wall material and exposes the starch for full digestion in mashing.

Malt Agar

A simple microbiological growth media used in the laboratory for yeasts and molds. Produced by mixing malt extract with up to 2% agar.

Malt Extract

A thick syrup or dry powder prepared from malt and sometimes used in brewing (often used by new homebrewers).


Malt production involves steeping the grains in 2 or 3 changes of water for 2-3 days to stimulate germination. Germinating grains are spread on open floors (floor malting), in long Saladin boxes or in automatic vessels with rotating arms mix and control the growth. When the grains have developed sufficiently to produce adequate levels of enzymes they are dried in a kiln. Low temperature drying, less than 120oC, will preserve enzyme activity. Higher temperatures will roast the grain producing flavours but remove enzyme activity.


A major disaccharide sugar produced by digestion of starch in mashing. b amylase specifically hydrolyses the non reducing end of starch chains to release maltose which comprises between 40 and 50% of the total sugar produced by the digestion. Composed of two glucose bound together maltose is readily fermented by yeast.


A major sugar produced by digestion of starch in malting. a amylase releases maltotriose from starch chains by random hydrolysis. Maltotriose is fermentable by most brewing yeast but this depends on the health of the yeast. Old, stressed or continually repitched yeast may be less efficient at fermenting maltotriose and so leave the beer with an incomplete fermentation and an undesirably high final gravity.

Mash Filter

A large scale means of separating the mash solids from the wort at the end of mashing. Mash filters compress the mash in a large press allowing wort through filter cloth and retaining solids. Extraction of sugars may be more efficient than standard mash tun separation but the wort may be cloudier. Really only applicable to bulk production due to the high capital cost of the equipment.


The first major stage in the brewing process where malt and liquor are mixed and left to incubate at set temperature(s). Starch is digested to simple sugars and many compounds are released from the malt to enrich the wort. Infusion mashing maintains a constant temperature, generally between 600 and 680C while temperature programmed and decoction mashing increases the temperature in steps from 350C to 450C to 650C and finishing at 750C to curtain enzyme activity. Temperature programmed mashing is most suitable for poorly modified malt and allows rests at temperatures optimal for the digestion of b glucans, protein and starch respectively.

Mashing Out

The process of raising the mash temperature to 1700F. The goal being to halt any enzymatic activity and prevent further conversion of starches to sugars.


Darkly pigmented compounds produced by the combination of simple sugars and amino acids. This reaction is accelerated by heating and mostly occurs during boiling. A range of melanoidins is produced from the different sugars and amino acids in the wort and also depends on the time of boiling. Melanoidins are good oxygen scavengers and can protect wort against oxidation and staling.


Distinctive flavor compounds with the aroma of skunk. Produced by the photolysis of a side chain of iso a acids and the subsequent reaction of this with sulphur containing thiol radicals to produce 3-methyl-2-butene-1-thiol. Exposing beer to light, particularly by using clear glass bottles, will initiate this reaction although specially treated hop oil, Tetra hop, will stabilize the iso a acid.


As defined by the Brewers Association: A brewery that produces less than 15,000 barrels of beer per year with 75% or more of its beer sold off-site.


Milling crushes grains before mashing and so exposes the internal contents to the mash liquor and enhances dissolving and digestion by enzymes. Mills crush grain between two, four or six rollers running in opposite directions and are set to break open the grain but not to crush it into flour. Part crushing is particularly important to ensure that the husk is retained to provide the filter bed for separating wort at the end of mashing.


The physical and chemical changes in barley that result from malting, especially the development of enzymes that are required to modify the grain’s starches into sugars during mashing, and also the physical changes that render the carbohydrate found in barley kernels more available to the brewing process. The degrees to which these changes have occurred, as determined by the growth of the acrospire.

Modified Malts

Modified Malts refers to the length of the germination process and how many of the internal malt structures and compounds have already been broken down.


The textures one perceives in a beer. Includes carbonation, fullness and aftertaste.


One of the essential oils made in the flowering cone of the hops plant Humulus lupulus.


Natural Carbonation

Sugar is added to beer in its container and then sealed. Fermentation kicks off again as the yeast eats the new sugar addition. When yeast ferments, it releases CO2 which is then absorbed into the liquid.


Ninkasi was the ancient Sumerian tutelary goddess of beer (and alcohol). Symbolizing the socially important role of women in brewing and preparation of beverages in ancient Mesopotamia.


The addition of nitrogen gas to beer to produce a smoother palate on dispense. Nitrogen is poorly soluble in beer and requires a high pressure to dissolve. On dispense much of the gas leaves the beer producing small bubbles which provide a tight, compact head.


Potentially carcinogenic compounds produced from amides or amines in wort, usually by bacterial action. Levels are low today due to control over the brewing process and reduction in microbial contamination.

Noble Hops

Noble hops are varieties that brewers use for their highly prized for their characteristic flavor and aroma. Traditionally these are grown only in four small areas in Europe: Hallertau in Bavaria, Germany; Saaz in Zatec, Czech Republic; Spalt in Spalter, Germany; Tettnang in the Lake Constance region, Germany.

Nonflocculating Yeast

Bottom fermenting yeast that do not form clumps while fermenting.


A term used in tastings to describe the overall fragrance, aroma and bouquet of a beer or wine.


Like any living creature, yeast require nutrients to remain healthy while performing their duty (i.e. fermentation). The essential nutrients are nitrogen and phosphorous, which are typically packaged and sold as “yeast nutrients” to add right after pitching your yeast.



A farm-based facility where hops are dried and baled after picking.


A term used to describe any taste in a brew that is inconsistent with the style or is just offensive. These flavors are often caused by poor sanitation, excessive aging and oxidation.


Oktoberfest in Munich
Oktoberfest is a beer festival held annually in Münich for 16 days and nights in late September and early October. It originally celebrate a royal wedding in 1810. It’s also a style of beer.

Original Gravity (OG)

The specific gravity of wort before fermentation. A measure of the total amount of solids that are dissolved in the wort as compared to the density of water, which is conventionally given as 1.000 and higher.


This is a flaw in bottling where too much sugar is added to the brew before bottling or kegging. The result is an over carbonated brew, or worse case scenario “bottle explosion.”

Oxalic Acid

An organic acid released into wort from barley and other grains. Can complex with calcium to produce precipitated crystals of calcium oxalate.


A chemical reaction in which one of the reactants (beer, food) undergoes the addition of or reaction with oxygen or an oxidizing agent.



A protease enzyme produced by the pineapple plant. May be used in beer to reduce protein levels and protect against haze.


Paraflow heat exchangers are used to heat or cool bulk volumes of beer. They are typically constructed of a series of parallel plates of stainless steel with wort or beer running across one side and chilled water or steam across the other. The rate of heat exchange is a function of the flow rate of the product passing through.

Party Pump or Picnic Pump

A party pump is a manual hand pump (typically used at parties or special events) that uses compressed air to dispense beer instead of CO2 gas. When using a party pump, you should always remember to keep the beer cold to prevent it from warming up and causing foaming. You should only use this type of pump if the beer will be consumed in 8 to 12 hours, as the beer will spoil much more quickly than beer dispensed from a kegerator using CO2.


The heat treatment of beer to kill microorganisms and provide stability to brewery processed beer. Flash pasteurization is commonly conducted by passing beer through a heat exchanger heated with steam. The rapid flow of the beer ensures a limited time of contact of around 30 seconds at a temperature of 73oC and minimizes degradation effects on the beer. Despite this pasteurized beer often tastes oxidized and aged due to the oxidization of components at the high temperatures. Pasteurization is measured in pasteurizing units (PU) which are defined as the effect on microorganisms of holding the beer at 60oC for one minute.


A group of substances which consists entirely of a long chain of galacturonic acid units, some of which are esterified with methyl alcohol; water dispersible. In the presence of acids and sugar, pectin forms the basis of household jellies.


A coccus variety of lactic acid bacteria with the ability to produce high levels of lactic acid and so readily spoil wort and beer. As with all lactic acid bacteria Pediococci are non-spore forming and gram negative. Unlike other lactic acid bacteria they are spherical in shape and are often distinguished by their diploid or tetrad arrangements of cells.

Permanently Soluble Nitrogen

The fraction of protein and other nitrogen compounds remaining after precipitation in the boil. These proteins will contribute to head formation and to mouthfeel and are an important component of beer.


Abbreviation for potential Hydrogen, used to express the degree of acidity and alkalinity in an aqueous solution, usually on a logarithmic scale ranging from 1-14, with 7 being neutral, 1 being the most acidic, and 14 being the most alkaline.


Cyclic organic compounds present in wort and often possessing distinctive flavors. Aromatic alcohol phenols are produced by yeast fermentation and may give beer a floral character above 200 mg per liter. Other phenols are less attractive. Chlorophenols produced by the reaction of phenol with chlorine are very pungently medicinal at very low levels. Spicy, clove like flavors are produced by the decarboxylation of the phenol ferulic acid from malt into 4-vinyl guaiacol. This reaction is catalysed by wild yeasts but not brewing yeasts and indicates possible contamination of yeast or beer. It is, however, a desirable feature of wheat beers which thus require an appropriate yeast for an authentic production


Unit of measure.  1 Pin = 4.5 Imperial Gallons.

Pitching/Pitching Rate

Pitching is the process of adding yeast to wort to start fermentation and produce beer. The number of yeast cells added per volume of wort is referred to as the “pitching rate.” Pitching rates may be expressed in terms of volume of yeast slurry per barrel of wort or as numbers of cells per milliliter. A typical pitching rate for warm-fermented ales would be 1 million cells/ml/degree Plato original gravity.

Plato Degrees of Measurement

Plato units relate wort strength to the concentration of sugar in solution rather than the density. 1Plato is equivalent to 1 gram of sucrose dissolved in distilled water. For comparison a wort with a specific gravity of 1040 will be 10o Plato.

Polymerase Chain Reaction (PCR)

A molecular biology procedure whereby a single piece of DNA may be extracted from a sample and multiplied extensively to demonstrate the presence of a particular gene or organism. Currently being developed as an identification procedure for yeasts and beer contaminants but also to distinguish barley and hop varieties.


One quarter a barrel or one-half a keg. That is, 7.75 U.S. gallons or imperial gallons

Potential Alcohol

The estimated amount of alcohol that a final brew will have. This measurement is based on the pre-fermentation sugar content.

Primary Fermentation

The first stage of fermentation carried out in open or closed containers and lasting from two to twenty days during which time the bulk of the fermentable sugars are converted to ethyl alcohol and carbon dioxide gas. Synonym: Principal fermentation; initial fermentation.

Priming Sugar

Sugars added to beer after fermentation to restart yeast activity and fermentation. Important in some cask ales and bottle conditioned beers where a secondary fermentation is necessary to produce additional carbonation. Sucrose would commonly be used but malt gives a better flavor profile.


A law instituted by the Eighteenth Amendment to the U.S. Constitution (stemming from the Volstead Act) on January 18, 1920, forbidding the sale, production, importation, and transportation of alcoholic beverages in the U.S. It was repealed by the Twenty-first Amendment to the U.S. Constitution on December 5, 1933. The Prohibition Era is sometimes referred to as The Noble Experiment.


Proteolytic enzyme which breaks down high molecular weight proteins into lower molecular weight. Proteases in malt are active during the protein rest at 40°C.-55°C. in the mash. Commercial proteases of plant, fungi, or bacterial origin are used in the brewhouse to supplement malt protease and more prominently in the cellar to chillproof the beer.

Proteolytic Enzymes

Enzymes found in malt which digest proteins into polypeptides and amino acids. They are very active in malting where much of the barley protein is digested. In poorly modified malt it may be necessary to further digest protein in mashing by a temperature infusion at 50-55oC to avoid beer hazes from excess protein remaining in the wort.


Pulque is a Mexican cactus beer.


A narrow mouth flask used for determining the specific gravity of wort or beer.



To drink a beverage, especially an intoxicating one, copiously and with hearty enjoyment.


Phenolic compounds produced by the oxidation of polyphenols. Can act as oxidizing agents themselves in wort and so produce stale flavors.



The process of transferring beer from one vessel to another, especially into the final package or keg.

Racking Cane

A plastic tube with an arced end that is attached to a hose and used to siphon brew. The arced end stays above the solids when lowered to the bottom of a fermenter and helps to leave sediment behind.

Real Ale

A style of beer found primarily in England, where it has been championed by the consumer rights group called the Campaign for Real Ale (CAMRA.) Generally defined as beers that have undergone a secondary fermentation in the container from which they are served and that are served without the application of carbon dioxide.

Real Extract

The extract in dealcoholized beer.


The Réaumur scale is a way of measuring temperature. The unit associated with the scale is called Réaumur, named after the physicist René-Antoine Ferchault de Réaumur who created it in 1731. The unit is usually abbreviated ‘Ré,’ sometimes ‘r’. The two base points of the scale are 0° the melting point of ice and 80° the boiling point of water, both at normal pressure. One degree Réaumur is the 80th part of that temperature difference.


Substance such as ammonia, fluorocarbons (e.g., Freon) and less frequently CO2 and SO2 capable of removing heat from their surroundings by boiling at the desired temperature under economical and safe operating conditions. 

Regional Craft Brewery

As defined by the Brewers Association: An independent regional brewery having either an all malt flagship or has at least 50% of its volume in either all malt beers or in beers which use adjuncts to enhance rather than lighten flavor.


A gas control valve that delivers a set gas pressure regardless of tank pressure. There may be a primary regulator on the gas source and a secondary regulator at the gas connection for each keg. The primary CO2 regulator attaches to the gas source, a bottle, or a bulk tank and is used to decrease the tank’s high gas pressure to a lower pressure. A primary regulator may be adjusted to the ideal gauge pressure and connected by gas line directly to a keg coupler, or may be installed to provide gas pressure to a secondary CO2 regulator. It utilizes a female connector in order to connect to the gas source. A primary nitrogen regulator is similar to a CO2 regulator but is used for nitrogen gas. It utilizes a male connector to connect to the source of the nitrogen. A secondary regulator is a regulator not connected directly to the gas source and is normally located in the cooler. Typically, the secondary regulator is installed between the primary regulator and a keg coupler to enable the ideal gauge pressure to be set for individual beer kegs.


The German beer purity law passed in 1516, stating that beer may only contain water, barley and hops. Yeast was later added after its role in fermentation was discovered by Louis Pasteur.

Residual Alkalinity

A measurement of the mash’s ability to buffer, or resist, attempts to lower its pH.

Residual Sugar

Any leftover sugar that the yeast did not consume during fermentation


During the mash, brewers hold the mash at a predetermined temperature in order to draw out certain enzymes from the grain.


An acronym for Recirculating Infusion Mash System, a type of brewing system that many homebrewers use.


Turbulent action in a liquid caused by mechanical agitation or introduction of a gas.

Ruh (G)

Period of storage after main fermentation.


A synonym for wort, or the liquid that you separate from the spent grain husks during lautering.



Saccharification occurs during the mash when the diastatic enzymes start acting on the starches, breaking them up into sugars.


glass saccharometer
A saccharometer is an instrument for measuring the amount of sugar in a solution, as by determining the specific gravity of the solution. It is usually calibrated directly to give a reading of concentration.


The genus of yeast which are particularly adapted to fermentation of strong sugar solutions and which thus produce high levels of alcohol. Saccharomyces cereisiae is the traditional brewing yeast and produces the typical flavor balance characteristic of beer. Other Saccharomyces yeasts also ferment but produce high levels of other flavors such as the spicy 4-vinyl guaiacol or the butterscotch diacetyl which are not so desirable. These Saccharomyces yeasts would be considered contaminants and may be termed wild yeasts. Saccharomyces diastaticus is a particularly undesirable contaminant in that it has the ability to ferment dextrins by producing amylase enzymes. As a result the beer becomes over fermented and lacks the body provided by the unfermentable sugars.


Known by brewers as Sarcina, (Pediococcus cerevisiae), is probably one of the most feared bacterial brewery contaminants, and may cause a condition in beer known as “sarcina” sickness. The main symptom is an unpleasant taste caused by diacetyl, a metabolic product of the organism. In many cases the change in taste may be accompanied by turbidity

Secondary Fermentation

The second, slower stage of fermentation for top fermenting beers, and lasting from a few weeks to many months, depending on the type of beer, and initiated by priming or by adding fresh yeast.


The refuse of solid matter that settles and accumulates at the bottom of fermenters, conditioning vessels and bottles of bottle-conditioned beer.


The wooden plug sealing the top of a cask. The shive contains a central plug which is opened to the air before dispense. Wooden pegs called spiles are inserted in the center of the shive to control air inlet and gas release from the beer. Porous spiles allow air through but reduce contamination from particles and are used during the serving period. Impermeable, hard spiles are used to temporarily seal the cask between serving periods.

Silica Hydrogel

Commonly known as lucilite, silica hydrogel specifically absorbs proteins and polypeptides from wort. The particles are added to beer during maturation or at filtration and can act in as little as 5 minutes to adsorb polypeptides with an isoelectric point between 3.0 and 5.0. As a result they are used in clarification and stabilisation, particularly when a long shelf life is required.

Slack Malt

Malt which has absorbed water and become soft and stale.

Solvent-like Flavor

Solvent-like Flavor and aromatic character similar to acetone or lacquer thinner, often due to high fermentation temperatures


A taste perceived to be acidic and tart. Sometimes the result of a bacterial influence intended by the brewer, from either wild or inoculated bacteria such as lactobacillus and pediococcus.


In lautering  sparging is washing of grains at the end of mashing to remove residual sugars and maximize extract.  Sparging consists of spraying the spent mash grains with hot water to retrieve the liquid malt sugar and extract remaining in the grain husks. Ideally using treated liquor at 77oC to reduce viscosity and terminate enzyme activity.

Specific Gravity

Specific gravity in the context of fermenting alcoholic beverages, refers to the specific gravity, or relative density compared to water, of the wort or must at various stages in the fermentation.The density of a wort is largely dependent on the sugar content of the wort. Several different scales have been used for measuring the original gravity. For historical reasons, the brewing industry largely uses the Plato scale (°P), which is essentially the same as the Brix scale used by the wine industry. For example, OG 1.050 is roughly equivalent to 12°P.

Spent Grains

The solids remaining at the end of sparging. Consisting of husks, barley embryo, roots and shoots, undissolved starch grains and precipitated proteins and tannins. Spent grains are typically used as animal feed or for composting but may have occasional uses in foods such as biscuits and beer bread.


A faucet used to regulate the flow of liquids from the bunghole of a barrel.


Small, wooden pegs or plugs, used to close vent holes in barrels.

Standard Reference Method (SRM)

Standard Reference Method (SRM) Chart
An analytical method and scale that brewers use to measure and quantify the color of a beer. The higher the SRM is, the darker the beer. In beer, SRM ranges from as low as 2 (light lager) to as high as 45 (stout) and beyond.


The major storage polysaccharide in barley endosperm cells. Produced by the polymerisation of glucose molecules starch has two molecular species, the linear polymer amylase (around 20%) and the branched polymer amylopectin (around 80%). Starch molecules are condensed into rigid starch grains during growth of the barley grain. These grains provide an inert energy store for when the grain germinates and are of two types, small grains 1-5m diameter and large grains 10-25m diameter. Mashing rapidly dissolves the small grains but most dissolved starch derives from the larger grains.

Steam Beer

Anchor Steam beer label
Steam Beer is a highly effervescent (high carbon dioxide content) beer made by top fermenting lager yeasts at warmer ale yeast fermentation temperatures that originated in California. Modern steam beer, also known as California common beer, was originated by Anchor Brewing Company, which trademarked the term Steam Beer in 1981. While steam beer is considered a specialty microbrew style of beer today, it was originally a cheap beer made for blue collar workers.


Similar to mashing, steeping adds fermentable sugars to the brew, and can provide a large variety of flavors and colors in the beer. The steeping process is done before the boil when grains are typically put in a steeping bag and immersed in the brewing water. Alternatively they can be steeped in a separate pot while the main boil is being prepared. Not all grains are suitable for steeping.

Step Infusion

A mashing method wherein the temperature of the mash is raised by adding very hot water, and then stirring and stabilizing the mash at the target step temperature.


Lipids which are essential for yeast membrane growth. Sterols contribute to the flexibility of yeast membranes and require oxygen for their synthesis by the yeast cell. Although yeast may multiply extensively without oxygen during fermentation they must be exposed to oxygen before a further pitching so that they have an opportunity to produce sterols. This will typically happen during cropping but many brewers aerate their collected worts before fermentation to ensure that their yeast is fully prepared.


A support for casks when positioned in the cellar. Stillaging is necessary so that yeast may settle into the belly of the cask and not be pulled out into the beer when it is dispensed through the tap. Stillages are usually two bars of wood or steel with the rear bar raised slightly higher than the front bar. The cask is further raised during dispense by placing chocks under the rear edge to assist flow.

Strike Temperature

The temperature of the brewing liquor which is added to the mash. This is typically between 750 and 800C to compensate for the lower temperature of the mash and adjusted to achieve a final temperature in the mash of 60-700C. A high strike temperature is also desirable to swell and gelatinise the starch grains and so expose them to digestive amylase enzymes.


Common table sugar, sucrose is a disaccharide composed of molecules of glucose and of fructose bonded together. Only small amounts (<5%) of sucrose are found in malt but sucrose may be added to wort as an adjunct and after fermentation as a priming

Sunstruck Beer

Beer which has been photolysed by light. The photolysis releases a side chain of iso a acids and the subsequent reaction of this with sulphur containing thiol radicals to produce 3-methyl-2-butene-1-thiol which has the characteristic smell of skunk.



A group of organic compounds contained in certain cereal grains and other plants. Tannins are present in the hop cone. Also called “hop tannin” to distinguish it from tannins originating from malted barley. The greater part of malt tannin content is derived from malt husks, but malt tannins differ chemically from hop tannins. In extreme examples, tannins from both can be perceived as a taste or sensation similar to sampling black tea that has steeped for a very long time.

Temperature Programmed Mashing

A mashing regime which involves a stepped increase in temperature during the mash. Typical steps involve one temperature stands at 35-40 oC for digestion of b glucans, another at 50 oC for digestion of proteins, a third at 65 oC for digestion of starch and a final rise to a 75oC mash-off to stop enzyme activity by denaturation.


The inner of three protective layers around the barley grain and composing the husk.


Heat resistant microorganisms undesirable in brewing.


A method, or the process, of using a standard solution to determine the strength of another solution.

Top Fermenting Yeast

One of the two basic fermentation methods characterized by the tendency of yeast cells to rise to the surface of the wort during fermentation. These yeasts remain on the surface as a yeast head and may be skimmed for repitching in a future brew.  In general ale yeasts are top fermenting whilst lager yeasts are bottom fermenting. Beers brewed in this fashion are commonly known as ale or top-fermented beers.


An order of monks that have produced beer for over a millennium. There are seven Trappist breweries still in operation in Belgium and the Netherlands. Strict regulations prevent non-Trappist Abbey breweries from using the term.


A storage sugar found in yeast and providing energy reserves and stress protection. High levels (15% of dry weight) may develop towards the end of fermentation in preparation for dormancy before the next exposure to sugars and subsequent fermentation. Trehalose acts like glycogen in providing readily available energy but is unique in becoming intimately associated with cell membranes to stabilize them against stress conditions such as high temperature, high ethanol levels and desiccation.


Precipitated proteins, tannins and lipids produced in hot wort during boiling and in cold wort after collection in the fermenter. Ideally should be left behind in the copper and fermenter when wort and beer are racked to another vessel as may cause haze and encourage microbial growth.


1. A large brewer’s fermenting vat or cask for holding liquids, especially wine or beer.

2. An imperial measure of liquid capacity, usually equivalent to 252 gallons or equal to 4 hogsheads.


Turbidity is the cloudiness or haziness of a fluid caused by large numbers of individual particles that are generally invisible to the naked eye, similar to smoke in air. The measurement of turbidity is a key test of water quality.


U.K. Gallon (Imperial or British Gallon)

An imperial gallon is 4.54 liters or 1.2 U.S. gallons.


Beer that is stale or infected and therefore cannot be sold. Often returned by the publican to the brewery.


Umami is the flavor of glutamic acid (MSG). Beers properly aged on yeast sediment can develop umami-like character


The sludge contained between the false bottom and the real bottom of a straining tank. It consists of rather hard parts of the mash and contains at times considerable amounts of starch.

Undermodified Malt

Malt containing barley or other grains that have been kilned or dried out in a way that prevented all the enzymes from transforming into proteins.


A term used to describe worts that have not been sufficiently aerated for fermentation. Yeast need an adequate amount of oxygen to effectively convert sugar to alcohol (and CO2).


Unfiltered is beer that brewers have not filtered to remove yeast.


A fermentation vessel which may also be used for conditioning. Common in a large scale production.


The process of emptying the steeped malts from the steeping vessel.


The sludge on top of the layer of grains in a straining tank, consisting of finely divided light particles, mostly coagulated protein.


Vacuum Evaporation

Removal of alcohols from beer by means of exposure to low pressures and enhanced evaporation of volatile compounds


Usually a fermenting or storage vessel. Early breweries typically used large copper vats in the brewhouse. A very few breweries still use wooden vats for fermentation but wood is difficult to keep clean and infection-free and must be repitched often.

Vent Hole

A small hole to allow air to escape.

Vicinyl Diketones (VDK)

Molecules with a double aldehyde group produced during fermentation by nitrogen metabolism. The common VDK is diacetyl produced from acetolactate, an intermediate of valine metabolism. Acetolactate is released into the wort and decarboxylates to diacetyl which has a very strong butterscotch flavor at low concentrations. Levels rise towards the end of fermentation but diacetyl is then reduced by yeast to produce 2,3 butanediol, a compound with a much higher flavor threshold. These reactions occur during normal processing but if yeast is removed too early high levels of diacetyl may result in beer.


Vinous is wine-like.


The resistance offered by a fluid (liquid or gas) to flow. The viscosity is a characteristic property and is a measure of the combined effects of adhesion and cohesion.


A test of yeast functioning which measures the metabolic ability of yeast. Tests use the rate of uptake of oxygen when fermenting sugars or the release of acid and reduction in pH as an index of vitality. The higher the vitality the better the yeast’s fermentative potential.

Volumes of C02

The measurement of c02 dissolved in a beer and is an indication of the carbonation level.


Vorlauf is the process of clarifying the wort being drawn out of the mash tun. Often this is as simple as drawing 1-2L of wort at a time slowly into a container and then pouring softly back onto the top of the mash; taking care to disturb the grain bed as little as possible.


Wallerstein Media

An agar medium used for the laboratory growth and characterization of yeasts. Wallerstein nutrient agar (WLN) contains bromomethyl green dye which may be taken up to different extents by different yeast strains so distinguishing their colonies. Wallerstein differential agar (WLD) also contains actinomycin, an antibiotic which inhibits yeast growth. WLD media is used to show the presence of bacteria in a beer or wort sample.


One of the four ingredients in beer. Some beers are made up by as much as 90% water. Globally, some brewing centers became famous for their particular type of beer, and the individual flavors of their beer were strongly influenced by the brewing water’s pH and mineral content. Burton is renowned for its bitter beers because the water is hard (higher PH), Edinburgh for its pale ales, Dortmund for its pale lager, and Plzen for its Pilsner Urquell (soft water lower PH).

Water Treatments

Treatments to adjust and control the acidity of the mash, usually by the addition of acid to neutralize the bicarbonate salts and by addition of calcium salts to enhance the release of acid from phytate. Typical treatments may be to add sulphuric acid to the hot liquor followed by a mixture of calcium sulphate and calcium chloride to the mash.

Wet Hopping

The addition of freshly harvested hops that have not yet been dried to different stages of the brewing process. Wet hopping adds unique flavors and aromas to beer that are not normally found when using hops that have been dried and processed per usual.


Round cylindrical flat bottom tank into which hot Tank wort from the brew kettle is pumped at high velocity and tangentially to its straight wall. This high speed stream causes the wort in the tank to rotate slowly and do deposit its trub in a more or less compact cone in the center of the tank.


A device inserted into a beer can to induce the rapid release of nitrogen gas when the pressure is release on opening. The rapid release results in many small bubbles which form a thick, creamy head which lasts longer than a carbon dioxide head.

Wild Yeasts

Non brewing yeasts are commonly called wild. Even non brewing strains of Saccharomyces cerevisiae may be termed wild in a brewery if they alter the beer flavor or affect the fermentation performance of the standard brewing yeast. Most wild yeasts found in beer are of a different Saccharomyces species or a different genera such as Pichia, Bretannomyces or Hansenula and produce distinctive flavors as well as turbidity.


The last stage of germination before the “piece” is put on the kiln; in early maltings this was generally done on a separate floor on the same level as the kiln, and to which the couch or “piece” was thrown, two days before being loaded on the kiln.


The sugar solution produced by the mashing process. Wort also contains proteins, amino acids, phenols, vitamins and minerals and is an excellent medium for the growth of microorganisms. The major sugar in most worts is maltose (40-45%) but glucose (12%), maltotriose (15%) and dextrins (20-25%) are also present.

Wort Chiller

A device to rapidly cool wort.  Usually copper tubing that has cold water running through it. Sometimes two tubes, one inside the other, with wort going through one and cold water going through the other.  Also called heat exchanger.



The basic sugar of pentosan compounds found in malt cell walls. Pentosans are not easily digested but those that are will release xylose into the wort.



A microscopic fungus. Over 700 species are recognized but all share a common single celled morphology with a rigid cell wall and an eukaryotic cell structure. Most yeasts reproduce by budding and many produce spores which help resist adverse conditions. The common brewing yeast is the species Saccharomyces cerevisiae which has the ability to ferment high sugar concentrations and may be distinguished by this in identification tests.

Yeast Cake

Living yeast cells compressed with starch into a cake, for use in brewing.

Yeast Crop

Yeast collected from fermentors during or after the fermentation.

Yeast Pitching

The point in the brewing process in which yeast is added to cool wort prior to fermentation.


Yeast like flavor; a result of yeast in suspension or beer sitting too long on sediment.

Yield of …

Number of pounds of extract, obtained from 100 pounds of brewing material, given in percent. Also kilos extract per kilo brewing material. Distinguish between laboratory yield of malt and adjunct which is determined by standard ASBC methods and brewhouse yield, which depends on equipment and operating conditions. Brewhouse yield ranges from 92 to 98% of laboratory yields.



The standard measurement of packaged hops. One zentner of whole leaf hops is equivalent to 50Kg.


A group of enzymes (originally found in yeasts and bacteria) which, in the presence of oxygen, convert glucose and a few other carbohydrates into carbon dioxide and water or, in the absence of oxygen, into alcohol and carbon dioxide or into lactic acid.

Zymology or Zymurgy

The branch of chemistry that deals with fermentation processes, as in brewing.

Zymonomas Mobilis

A pernicious bacterial contaminant of beer. Zymonomas mobilis is the major species found and produces very distinctive vegetal off flavours as well as some lactic acid so rapidly spoiling beer. The bacteria grows particularly well with glucose and sucrose and is most likely to contaminate primings or beer primed for cask conditioning.


Greek name for barleywine



18th Amendment

The 18th amendment of the United States Constitution effectively established the prohibition of alcoholic beverages in the United States by declaring illegal the production, transport and sale of alcohol (though not the consumption or private possession).

21st Amendment

The 21st amendment to the United States Constitution repealed the Eighteenth Amendment to the United States Constitution, which had mandated nationwide Prohibition on alcohol on January 17, 1920