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.
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.
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)
- 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.
- 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 entirely from mashed barley malt and without the addition of adjuncts, sugars or additional fermentables.
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.
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.
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.
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.
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.
Grayish-brown deposit formed from calcium and fermentation byproducts on the surface of equipment in prolonged contact with beer.
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.
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)
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.
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.
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.
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.
One of the vessels used in the brewing process in which the wort (unfermented beer) is boiled
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.
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.
The aroma of Sulphur indicating the presence of sulphate ions.
Desirable and undesirable compounds that are a result of fermentation, mashing, and boiling.
A mineral common in water of different origins. Also known as chalk, sometimes added during brewing to increase calcium and carbonate content.
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.
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.
Caustic Soda, or NaOH (Sodium Hydroxide)
Storing or aging beer at a controlled temperature to allow maturing.
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.
Fermentation under closed, anaerobic conditions to minimize risk of contamination and oxidation.
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.
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.
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.
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.
An empirically derived hydrometer scale to measure density of beer wort in terms of percentage of extract by weight.
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 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.
Doughing in (or mashing in)
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)
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.
Dual Purpose Hops
Hops that are added to provide both bittering and aromatic properties.
EBC (European Brewing Convention)
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
Any beer produced for the express purpose of exportation. For example: export-style German lagers or export-style Irish stouts.
One of the essential oils made in the flowering cone of the hops plant Humulus lupulus.
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.
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.
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.
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.
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.
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.
Growth of a barley grain as it produces a rootlet and acrospire.
Glycol or Propylene Glycol
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.
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.
The foam stability of a beer as measured, in seconds, by time required for a 1-inch foam collar to collapse.
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.
The addition of hops to unfermented wort or fermented beer. See Dry Hopping or Wet Hopping for additional details.
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.
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.
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.
A wort chiller most commonly made of copper that is used by submerging into hot wort before fermentation as a method of cooling.
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.
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.
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.
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.
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.
An automatic machine used to wash bottles.
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 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.
Liter / Litre
Low Alcohol Beer
- A 1.5L bottle.
- 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.
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.
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.
A farm-based facility where hops are dried and baled after picking.
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.
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
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 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
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. 1o Plato 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.
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.
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.
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.
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.
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.
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.
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.
A measurement of the mash’s ability to buffer, or resist, attempts to lower its pH.
Any leftover sugar that the yeast did not consume during fermentation
Standard Reference Method (SRM)
Temperature Programmed Mashing
Top Fermenting Yeast
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.
U.K. Gallon (Imperial or British Gallon)
Beer that is stale or infected and therefore cannot be sold. Often returned by the publican to the brewery.
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.
A fermentation vessel which may also be used for conditioning. Common in a large scale production.
The sludge on top of the layer of grains in a straining tank, consisting of finely divided light particles, mostly coagulated protein.
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.
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.
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
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.
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).
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.
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.
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 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.
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.
Living yeast cells compressed with starch into a cake, for use in brewing.
Yeast collected from fermentors during or after the fermentation.
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.
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.
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).
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