Beer Glossary

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 AAU's (Alpha Acid Units)
Alpha Acid Units (AAU's) are a measurement of the amount of alpha acids added to a beer. Equals to the amount of hops, in ounces, multiplied by the percentage of alpha acids in the hops. This is a very rough measurement of bitterness and usually only used in homebrewing. Alpha Acid Units are also sometimes refered to as Homebrew Bittering Units or HBU's
Acid Rest
A relatively low temperature rest (95F) used to activate the phytase enzyme, the desired result of which is to lower the pH of the mash. This is generally only employed in Germany where the Reinheitsgebot prevents the use of things like acid blend which serve the same purpose. A small amount of acid malt is used.
Acrospire
The beginnings of the plant shoot in germinating barley.
Additives
Ingredients used in beer production that are not adjuncts, malt, hops, water or yeast. Additives can be added at any stage of the brewing process and are not removed before the beer is consumed (unlike processing aids that are removed). Substances such as spices, flavorings, enzymes and yeast nutrients are considered to be additives.
Adjunct
Any fermentable, unmalted grain or ingredient, other than barley malt, added to the mash to provide fermentable sugars in the brewing process, including corn, corn sugar, oats, wheat and rice. Many of the world's largest breweries utilize adjuncts to reduce production costs and create lighter tasting beer. Other adjuncts are used to create a unique mouthfeel in specialty beers or change the composition of the wort.
Aerate
To mix air into solution to provide oxygen for the yeast.
Aerobic
A process that utilizes oxygen.
Alcohol
Ethyl alcohol or ethanol. An intoxicating byproduct of fermentation, caused by yeast consuming sugars in the malt.
Alcohol by Volume (abv)
Percentage of alcohol content in a beverage, by volume. The percentage of alcohol by weight is approximately 20 percent lower than that by volume.
Alcohol by Weight (abw)
Percentage of alcohol content in a beverage, by weight. The percentage of alcohol by weight is approximately 20 percent lower than that by volume.
Alcohol content
Alcohol content is expressed as a percentage of volume or weight.
Alcoholic
A warming flavor or aroma derived from ethanol and higher alcohols. Some people think it has a salty taste.
Aldehyde
A chemical precursor to alcohol. In some cases, alcohol can be oxidized to aldehydes, creating off-flavors.
Aldehydic
Nutty, toffee, honey, or green apple flavors and aromas in beer caused by degradation of amino acids or oxidation of isohumulones and lipids.
Ale
Beers brewed with top-fermenting yeast strains. The top-fermenting yeast performs at warmer temperatures than yeasts used to brew lager beer.
Aleurone Layer
The living sheath surrounding the endosperm of a barley corn, containing enzymes.
Alkalinity
The condition of pH between 7 and 14. The chief cause of alkalinity in brewing water is the bicarbonate ion (HCO3-1).
All-grain
A term used to describe the brewing process in which only malt grist is used with no malt extract added.
All-malt
A term used to describe beer made exclusively with malted barley and no adjuncts.
Alpha Acids
The main bittering compounds found in the lupulin glands of hop flowers. There are actually many different alpha acids, the main ones being humulone, cohumulone and adhumulone. Alpha acids are not very soluble at cold temperatures and must be isomerised before they can dissolve into beer.
Alpha Amylase
One of the two primary enzymes responsible for breaking starch down into sugar. Alpha amylase is most active in the upper range of mashing temperatures (155F-160F) and is responsible for producing higher-order (larger) sugars which are less fermentable, producing a beer with more body.
Amino Acids
An essential building block of protein, being comprised of an organic acid containing an amine group (NH2).
Amylase
An enzyme group that converts starches to sugars, consisting primarily of alpha and beta amylase. Also referred to as the diastatic enzymes.
Amylopectin
A branched starch chain found in the endosperm of barley. It can be considered to be composed of amylose.
Amylose
A straight-chain starch molecule found in the endosperm of barley.
Anaerobic
A process that does not utilize oxygen or may require the absence of it. The ability to metabolise without oxygen present e.g. bottom-fermenting lager yeast.
Aroma
The fragrance or smell of a beer.
Aroma Hops
Variety of hop chosen for its bouquet, which are typically added in the final stages of the boil or during the secondary fermentation in a process called "dry hopping."
Astringent
A usually undesirable puckering or sour characteristic in beer, which is usually caused during the brewing process by boiling grains, long mashes and oversparging. Drying, puckering taste; can be derived from boiling the grains, long mashes, over-sparging or sparging with hard water.
Attenuation
The degree of conversion of the sugars in the wort into alcohol and carbon dioxide during fermentation.
Autolysis
When yeast run out of nutrients and die, they release their innards into the beer, producing off-flavors.
  Balance
The level at which a particular beer's flavors relate to each other. Levels of malt and hops are typically adjusted to balance properly, however, other ingredients such as spices can contribute to balance as well.
Balling, Degrees
Scale indicating density of sugars in wort. Devised by C J N Balling. Used interchangably with Brix and Plato.
Barley
The primary ingredient in beer, which is germinated and then kilned to create malt. It is then mashed to create wort.
Barrel
A measurement or container of beer, which equals 31 gallons in the United States. The largest kegs that are currently used commercially hold 1/2 barrel of beer.
Beer
Any beverage made by fermenting a wort made from malted barley and seasoned with hops.
Beerstone
A hard organo-metallic scale that deposits on fermentation equipment; chiefly composed of calcium oxalate. Draft beer systems must be cleaned very regularly to prevent the buildup of beerstone which contributes off-flavors to beer.
Beta Amylase
One of the two primary enzymes responsible for breaking starch down into sugar. Beta amylase is most active in the lower range of mashing temperatures (149F-155F) and is responsible for producing lower-order (smaller) sugars which are more fermentable, producing a beer with less body.
Beta Glucanase
The enzyme which breaks down beta-glucans, which hold together branced starch molecules. This term is most commonly associated with George Fix, who championed the now famous 40/60/70 mashing schedule. The 40C rest breaks down beta-glucans, which in turn has been shown to give higher extraction yields.
Biotin
A colorless crystalline vitamin of the B complex, found especially in brewers yeast.
Bitter
The flavor most commonly derived from hops to balance the malt sweetness. The sensation is experienced on the back of the tongue, hence beer should never be spit out like wine during tasting. In England, a bitter is also a term used for pale ale.
Bittering Hops
Hops added at the beginning of the boil in order to obtain maximum alpha acid utilisation. Any type of hops can be used for bittering, although those higher in alpha acids will require the use of less hops per unit of beer.
Black Malt
Partially malted barley roasted at high temperatures. Black malt gives a dark colour and a roasted flavor to beer.
Blow-off
A type of airlock arrangement consisting of a tube exiting from the fermenter, submerging into a bucket of water, that allows the release of carbon dioxide and removal of excess fermentation material.
Body
The weight of a beer on the palate, ranging from thin or light-bodied to full-bodied. Thickness and mouth-filling property of a beer described as "full or thin-bodied".
Bottle Conditioned
A final fermentation, which occurs in the bottle by adding yeast and/or fermentable sugar to the beer before bottling. It may make the beer cloudy or leave a sediment in the bottom of the bottle.
Bottom Fermenting Yeast
One of the two primary types of yeast used in brewing. Bottom-fermenting yeast works well at low temperatures and ferments more sugars leaving a crisp, clean taste and then settles to the bottom of the tank. Also called "lager yeast".
Bouquet
See aroma.
Break Material
The break is the point in brewing when proteins coagulate, making a clearer beer. This happens both when the wort gets boiled, as well as when it chills quickly (see hot break and cold break). The material formed is called either break, or break material. It is generaly accepted that the more break you can get (or force), the better.
Brettanomyces
Brettanomyces is a non-spore forming genus of yeast in the family Saccharomycetaceae, and is often colloquially referred to as "Brett". The genus name Dekkera is used interchangeably with Brettanomyces, as it describes the teleomorph or spore forming form of the yeast. Brettanomyces contributes tartness to a beer during fermentation. In most beers, Brettanomyces is a contaminant suggesting of infected yeast. However, some beers, such as lambic, gueuze, Flemmish Sour Ales, and Flanders Red Ales, utilize Brettanomyces to intentionally add a thirst quenching tart quality which is described as anything from "sour cherry pie" to "sweaty horse saddle."
Brew Kettle
The vessel in which wort from the mash is boiled with hops. Also called a copper.
Brew on Premises (BOP)
Businesses that rent their facilities for do-it-yourself brewers to come in and brew their own beer.
Breweriana
Brewing memorabilia, such as old beer containers and advertisements.
Brewhouse
Equipment used to brew beer. The collective equipment used in beer production.
Brewpub
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. Note: BA re-categorizes a company as a microbrewery if its off-site (distributed) beer sales exceed 75 percent.
Bright Beer Tank
A vessel used as a holding tank just prior to bottling or kegging beer. Beer goes into the bright beer tank just following filtration (if filtering is done) and beer may be carbonated in it with a porous carbonating stone.
Brix, Degrees
A measurement of the mass ratio of dissolved sucrose to water in a liquid. It is measured with a saccharimeter that measures specific gravity of a liquid or more easily with a refractometer. A 25 °Bx solution has 25 grams of sucrose sugar per 100 grams of liquid. Or, to put it another way, there are 25 grams of sucrose sugar and 75 grams of water in the 100 grams of solution. Used interchangably with Plato and Balling.
Buffer
A chemical species, such as a salt, that by disassociation or re-association stabilizes the pH of a solution.
Bung
The stopper in the hole in a keg or cask through which the keg or cask is filled and emptied. The hole may also be referred to as a bung or bunghole.
  CAMRA
The Campaign for Real Ale, the British-based grassroots organization formed to educate, lobby and protect traditional cask-conditioned ale from becoming extinct.
Carbon Dioxide
A gas created from the fermentation process. Carbon dioxide gives beer its carbonation.
Carbonation
Sparkle caused by carbon dioxide, either created during fermentation or injected later. This terms is used to describe both the amount of CO2 in the beer, as well as the process of putting CO2 into the beer. See force carbonation and natural carbonation.
Cask
A closed, barrel-shaped vessel used for fermenting and serving beer. They used to be made of wood, but now most are made of stainless steel or aluminum. They are used for cask-conditioned ales, which need to be vented intermittently while they naturally carbonate. A standard sized cask is called a firkin, and a half-sized cask is called a pin.
Cask-Conditioned
Unfiltered, unpasteurized beer that is naturally carbonated by undergoing a secondary fermentation in its own serving vessel. Cask-conditioned beer is traditionally served slightly warmer than draft beer.
Cellulose
Similar to a starch, but organized in a mirror aspect; cellulose cannot be broken down by starch enzymes.
Ceravisaphile
(Cer-a-vehs-a-file) 1.an aficionado of beers and ales, 2.a devotee to the decoction of barley infused with hops and fermented, 3.an imbiber of beer on the highest order, bordering on devotion, 4.one who pursues the very finest in malted beverages.
Charge
A term used to describe the amount of malt used in a brew.
Chill haze
Cloudiness caused by precipitation of protein-tannin compound at low temperatures; it does not affect flavor.
Chlorophenolic
A plasticlike or chlorine like aroma; caused by chemical combination of chlorine and organic compounds. This can result from improper rinsing of brewing or fermenting vessels after the use of cleaning solvents.
Clarafying Agent
Commonly referred to as a fining. Any ingredient added in minimal quantities during the production process to improve the clarity of beer. Examples include Irish Moss and Isinglass.
Cold Break
Proteins that coagulate and fall out of solution when the wort is rapidly cooled prior to pitching the yeast.
Cold-Filtered
The process of filtering beer to remove sediments and contaminants, which improves the clarity of beer. Marketers use this term to connote a special process, but virtually all beer is "cold-filtered."
Conditioning
Period of maturation intended to impart "condition"(natural carbonation). Warm conditioning further develops the complex of flavors. Cold conditioning imparts a clean, round taste. An aspect of secondary fermentation in which the yeast refine the flavors of the final beer.
Conditioning Tank
A vessel in which beer is placed after primary fermentation where the beer matures, clarifies and is naturally carbonated through secondary fermentation. At some breweries, this vessel is also used as the bright beer tank, serving tank and/ or the secondary fermentation tank.
Contract Brewery
A company that markets, sells, and owns all rights to a beer brand but outsources the production of the beer to another brewery. Confusingly, breweries that offer these production services are also commonly refered to as contract breweries.
Cooper
Craftsperson who hand-builds beer kegs from wood.
Cooperage
Any vessel used to serve beer, including kegs, firkins, pins, etc.
Copper
See brew kettle.
Craft Beer
Craft beers are produced with 100 % barley or wheat malt or use other fermentable ingredients that enhance (rather than lighten) flavor. Craft beers only come from craft brewers.
Craft Brewer
An American craft brewer is small, independent and traditional. Craft beer comes only from a craft brewer. Small = annual production of beer less than 2 million barrels. Beer production is attributed to a brewer according to the rules of alternating proprietorships. FMB’s are not considered beer for purposes of this definition. Independent = Less than 25% of the craft brewery is owned or controlled (or equivalent economic interest) by an alcoholic beverage industry member who is not themselves a craft brewer. Traditional = A brewer who has either an all malt flagship (the beer which represents the greatest volume among that brewers brands) 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.
  DE (Diatomaceous Earth)
A naturally occurring, soft, chalk-like sedimentary rock that is easily crumbled into a fine white to off-white powder. This powder has an abrasive feel, similar to pumice powder and is very light, due to its high porosity. DE can be used during the filtration process to remove impurities from beer.
Decoction
A method of mashing wherein temperature rests are achieved by boiling a part of the mash and returning it to the mash tun.
Dextrin
A complex sugar molecule, left over from diastatic enzyme action on starch. Dextrin contributes flavor and body to a beer.
Dextrose
Equivalent to glucose, but with a mirror-image molecular structure.
Diacetyl
A buttery or butterscotch aroma or flavor created during yeast growth in the fermentation process. Diacetyl is frequently caused by a high-temperature fermentation, low pH in the fermenting wort, insufficient aeration at the start of fermentation, or the use of unhealthy or infected yeast.
Diastatic Power
The amount of diastatic enzyme potential that a malt contains.
DME
Dry malt extract. (See malt extract).
DMS (Dimethyl Sulfide)
A background flavor compound that is acceptable in low amounts in lagers, but that at high concentrations is the sign of bad beer. DMS can be caused by a dormant boil (as opposed to a vigorous one), a slow start to fermentation, or an extended delay between the end of the boil and the cooling to ideal fermentation temperature. DMS often grows in plate heat exchangers. The defining flavor characteristic of DMS is that of cooked vegetables, creamed corn, oysters, or tomato juice.
Draff
The material remaining in the lauter tun after sparging.
Draft
Dispensing beer from a bright tank, cask or keg, by hand pump, pressure from an air pump or injected carbon dioxide inserted into the beer container prior to sealing.
Dry Hopping
The addition of dry hops to fermenting or ageing beer to increase its hop character or aroma.
Dry Malt
A powdered form of malt, formed by dehydrating malt extract.
  Endosperm
The nutritive tissue of a seed, consisting of carbohydrates, proteins, and lipids.
Enzymes
Protien based catalysts found naturally in grain. When heated in mash they convert the starches of the malted barley into maltose, a sugar used in solution and fermented to make beer.
Ester
Volatile flavor compound naturally created during fermentation, most frequently with ales. Often fruity, flowery or spicy.
Ethanol
The form of alcohol produced by yeast during fermentation.
Extraction
The soluble material derived from barley malt and adjuncts. Not necessarily fermentable.
Extraction Efficiency
A measure of the amount of sugars obtained from the grains during the mash, compared with the theoretical maximum obtainable from the grains used. Note that homebrewers and professional brewers have completely different ways of calculating extraction efficiency, so the two figures they obtain are not directly comparable. See here for details.
  Fatty Acid
Any of numerous saturated or unsaturated aliphatic monocarboxylic acids, including many that occur in the form of esters or glycerides, in fats, waxes, and essential oils.
Fermentation
The process of yeast consuming soluble sugars in wort to create byproducts, primarily alcohol and carbon dioxide.
Filter
To remove designated impurities and haze by passing the wort through a medium, sometimes diatomaceous earth. Yeast in suspension is often targeted for removal.
Fining
Any ingredient such as isinglass, bentonite, or Irish moss, that acts to help the yeast to flocculate and settle out of finished beer. An aid to clarification: a substance that attracts particles that would otherwise remain suspended in the brew. Typically added early in the boil.
Finish
The resulting impression of a ber after it has been swallowed. A finish can be characterized as dry, lingering, short, etc.
Finishing/Final Gravity (f.g.)
A measure of wort's density at the end of fermentation. As the wort ferments, yeast converts maltose into alcohol and the gravity drops because alcohol is lighter that water. Before beer begins to ferment brewers take an original gravity reading (o.g.).
Firkin
A measurement or container of beer, which equals one quarter of a barrel (40.9 liters). The firkin is the most popular sized vessel for serving cask conditioned beer.
Flocculation
To cause to group together. In the case of yeast, it is the clumping and settling of the yeast out of solution.
Force Carbonation
The artificial addition of carbonation to beer by forcing it into suspension, resulting in slightly larger bubbles.
Fructose
Commonly known as fruit sugar, fructose differs from glucose by have a ketone group rather than an aldehydic carbonyl group attachment.
Fusel Alcohol
A group of higher molecular weight alcohols that esterify under normal conditions. When present after fermentation, fusels have sharp solvent-like flavors and are thought to be partly responsible for hangovers.
  Gelatinization
The process of rendering starches soluble in water by heat, or by a combination of heat and enzyme action, is called gelatinization.
Germination
Part of the malting process where the acrospire grows and begins to erupt from the hull.
Glucanase
An enzyme that act on beta glucans, a type of gum found in the endosperm of unmalted barley, oatmeal, and wheat.
Glucose
The most basic unit of sugar. A single sugar molecule.
Grain Bill or Malt Bill
The combination of all grains that will be used for a particular batch of beer. Prepared prior to milling and mashing.
Grainy
A raw grain flavor or aroma or flavor. Some graininess is acceptable in some beer styles.
Gravity
Like density, gravity describes the concentration of malt sugar in the wort. The specific gravity of water is 1.000 at 59F. Typical beer worts range from 1.035 to 1.055 before fermentation (Original Gravity).
Grist
The term for malt that is cracked or crushed prior to mashing. Brewers' term for milled grains, or the combination of milled grains to be used in a particular brew.
  Hand Pump
A device for dispensing draft beer using a pump operated by hand. The use of a hand pump allows the cask-conditioned beer to be served without the use of pressurized carbon dioxide.
Hardness
The hardness of water is equal to the concentration of dissolved calcium and magnesium ions. Usually expressed as ppm of (CaCO3).
Heat Exchanger
Equipment generally consisting of hundreds of plates or double layered coils, usually used after the boil for cooling wort quickly before yeast can be pitched in the wort.
Hogshead
Cask holding 54 imperial gallons ( 243 liters ).
Hop back
Sieve-like vessel used to strain out the petals of the hop flowers. Referred to as a hop jack in the United States.
Hoppy
A hop aroma or flavor of the essential oils of hops, which are derived from the lupulins of a hop flower. Ranging from floral to potpouri to piney to citrusy.
Hops
The green cone-shaped flowers from the female hop vine used to add flavor and aromatics as well as bitter to beer. Hop vines are grown in cool climates and brewers make use of the cone shaped flowers. The dried cones are available in pellets, plugs, or whole.
Hot Break
Proteins that coagulate and fall out of solution during the wort boil.
Hot Water Extract
The international unit for the total soluble extract of a malt, based on specific gravity. HWE is measured as liter*degrees per kilogram, and is equivalent to points/pound/gallon (PPG) when you apply metric conversion factors for volume and weight. The combined conversion factor is 8.3454 X PPG
Humulone
The orangey, soft resin in hops which is primarily responsible for the bittering properties of the hops.
Hydrolysis
The process of dissolution or decomposition of a chemical structure in water by chemical or biochemical means.
  IBU's (International Bittering Units)
A measurement of the iso-alpha acid concentration, which contributes bitterness to beer. The iso-alpha acid concentration is the major contributor to bitterness in beer. 1 IBU = 1 part per million of isomerised alpha acid.
Infusion
Simplest form of mash, in which grains are soaked in water. May be at a single temperature, or with upward or (occasionally) downward changes.
Invert Sugar
A mixture of dextrose and fructose found in fruits or produced artificially by the inversion of sucrose (e.g. hydrolyzed cane sugar).
Irish Moss
An emulsifying agent, Irish moss promotes break material formation and precipitation during the boil and upon cooling.
Isinglass
The clear swim bladders of a small fish, consisting mainly of the structural protein collagen, acts to absorb and precipitate yeast cells, via electrostatic binding.
Isomerisation
Isomerisation is the rearrangement of a molecule from one form (isomer) to another without gaining or losing atoms. This is important in brewing as a-acids are not very soluble in water whereas iso-a-acids are very soluble. Isomerisation of a-acids occurs when a-acids are heated. This traditionally has taken place in the Kettle when the hops are added, however, these days preisomerized hops and hop products are also available.
Isomerised Alpha Acids
Also known as Iso-alpha acids, Iso-alphas and Isos. Isomerised alpha acids are alpha acids that have been rearranged chemically without gaining or losing atoms (isomerised). Unlike unisomerised alpha acids, isomerised alpha acids are soluble in beer at storage and serving temperatures. Isomerised Alpha Acids are the main bittering component in beer.
Isovaleric Acid
An organic acid which results in a cheesy or "sweat sock" flavor in beer caused by the use of old hops.
  Keg
Container for beer. Originally made of wood and available in a variety of sizes. Many breweries employed their own coopers to make their kegs. Today the average beer keg in America contains 15.5 gallons, or 1/2 barrels of liquid.
Kräusen
Literally, "crown" in German. Used to refer to the foamy head that builds on top of the beer during fermentation. Today, refers to introduction of unfermented wort to fermented wort to continue or revive fermentation, either in the conditioning tank or just prior to bottling as an advanced method of priming. Kräusening stimulates an additional fermentation and imparts a crisp, spritzy character. (Pronounced kroyzen).
  Lactose
A nonfermentable sugar, lactose comes from milk and has historically been added to stout, hence the style lacto-stout or milk stout.
Lag Phase
The period of adaptation and rapid aerobic growth of yeast upon pitching to the wort. The lag time typically lasts from 2 to 12 hours.
Lager
Beers produced with bottom-fermenting yeast strains at colder fermentation temperatures than ales. Fermentation of lagers generally takes longer than that of ales.
Lagering
From the German word lagern, to store. Refers to maturation for several weeks or months at cold temperatures from 35 to 55 degrees Farenheit.
Lauter
To strain or separate. Lautering acts to separate the wort from grain via filtering and sparging. To run the wort from the mash tun. From the German word to clarify. A lauter tun is a separate vessel to do this job. It uses a system of sharp rakes to achieve a very intensive extraction of malt sugars.
Lauter Tun
The vessel in which mashed grain is sparged (lautered). Sometimes referred to mash-lauter tun because usually mashing and sparging occur in the same vessel.
Lead Conductance Value
The Lead Conductance Value (LCV) (also known as Conductometric Value or CV) is a widely utilised measurement used to estimate of the a-acid concentration and also bittering potential of recently harvested hops. The Lead Conductance Value is measured by extracting the a-acids from the hops with methanol and then titrating a solution of lead acetate, methanol and some acetic acid into the a-acid / methanol solution. The a-acids and lead form a bright yellow lead salt precipitate that is insoluble in methanol. During the titration the conductance of the titrated solution is measured. The conductance of the solution remains relatively stable until all the a-acids are bonded with the added lead, this is the end point or lead conductance value. After the end point has been reached the lead in the solution that does not bond with a-acids causes the conductance of the solution to rise in a linear manner. If the conductance of the titration is graphed then the result is two linear lines and a small curve around the end point. The true end, and therefore true lead conductance value, can be determined by extrapolating the linear lines and finding the point at which they intercept.
Light-struck
The skunky smell or flavor that results from a beer being exposed to too much direct sun or fluorescent lights. It is particularly pervasive in light beers packaged in green or clear bottles and is less common in beers packaged in brown bottles. It is caused by the reaction of hop oils to ultraviolet light.
Lipid
Any of various substances that are soluble in nonpolar organic solvents, and that include fats, waxes, phosphatides, cerebrosides, and related and derived compounds. Lipids, proteins, and carbohydrates compose the principal structural components of living cells.
Liquefaction
As alpha amylase breaks up the branched amylopectin molecules in the mash, the mash becomes less viscous and more fluid; hence the term liquefaction of the mash and alpha amylase being referred to as the liquefying enzyme.
Liquor
Brewer's term for hot or cold water used in the brewing process, as included in the mash or used to sparge the grains after mashing.
Liquor Tank
The vessel in which water for brewing is stored for rapid transfer to the mashing, lautering, or brewing vessels. It may store either hot or cold water.
Lovibond
A measure of the darkness of a malt, wort and beer. Pilsener malts are in the 1 to 3 degrees Lovibond range, Munich malt from 7 to 10, Crystal Malt can be a very wide range from 15 to 100, Chocolate malt starts around 200, and really dark malts like Black Patent can be over 450.
Lupulin Glands
Small bright yellow nodes at the base of each of the hop petals, which contain the resins utilized by brewers.
  Maillard Reaction
A browning reaction caused by external heat wherein a sugar (glucose) and an amino acid form a complex, and this product has a role in various subsequent reactions that yield pigments and melanoidins.
Malt
The foundation ingredient of beer after it has gone through the malting process, typically barley. Grain which has been sprouted and kilned.
Malt Extract
The condensed wort from a mash, consisting of maltose, dextrins and other dissolved solids. Either as a syrup or powdered sugar, it is used by brewers, in solutions of water and extract to reconstitute wort for fermentation.
Malting
The process by which barley is steeped in water, germinated, then kilned to convert insoluble starch to soluble substances and sugar.
Malto-Dextrin
Unfermentable carbohydrates which add body and head retention to beer.
Maltose
The preferred food of brewing yeast. Maltose consists of two glucose molecules joined by a 1-4 carbon bond. A water-soluble, fermentable sugar contained in malt.
Maltotriose
A sugar molecule made of three glucoses joined by 1-4 carbon bonds.
Mash
The porridge-like blend of water and grist at the beginning of the brewing process that releases sugars for brewing.
Mash Out
At the end of the final saccharification rest, raising the mash to 165-168F and holding for 10 minutes to denature (kill) the enzymes, and thereby fix the exact composition of the wort. This process improves extraction efficiency.
Mash Tun
A copper or stainless steel vessel used for mashing the grist and water. Literally, tun is "tub" in German.
Mashing
Converting starches into fermentable sugars through an enzymatic reaction induced by the steeping of malt in hot water.
Mead
Mead is produced by the fermentation of honey, water, yeast and optional ingredients such as fruit, herbs, and/or spices.
Medecinal
Chemical or phenolic character; can be the result of wild yeast, contact with plastic, or sanitizer residue.
Melanoidins
Strong flavor compounds produced by browning (Maillard) reactions.
Methanol
Also known as wood alcohol, methanol is poisonous and cannot be produced in any significant quantity in the beer making process.
Microbrewery
A brewery that produces less than 15,000 barrels (17,600 hectoliters) of beer per year. Microbreweries sell to the public by one or more of the following methods: the traditional three-tier system (brewer to wholesaler to retailer to consumer); the two-tier system (brewer acting as wholesaler to retailer to consumer); and, directly to the consumer through carryouts and/or on-site tap-room or restaurant sales.
Milling
Cracking the shell of malted grains to expose the starches inside to hot water during the mashing process.
Modification
An inclusive term for the degree of degradation and simplification of the endosperm and the carbohydrates, proteins, and lipids that comprise it.
Monastic
Any beer that is produced at a monestary.
Mouthfeel
The way a beer feels on the palate, such as viscose, thin, light, soft.
MTB (3-methyl-2-butene-1-thiol)
Undesired 'skunky' compound found in lightstruck Beer. Detectable in very low concentrations. 3-methyl-2-butene-1-thiol is also known as MTB.
Musty
Moldy, mildewy character; can be the result of cork or bacterial infection.
  Natural Carbonation
The creation of carbonation through a one to two week process of bottle or keg conditioning, whereby priming sugars and/or yeast create carbonation within an airtight vessel. This results in tiny, champagne like bubbles.
Noble Hops
Hop varieties stemming primarily from Germany, the UK and the Czech Republic, which have been in existance for a very long time. Most other hop varieties trace their origins to the noble ones, which are characterized by low levels of bitterness. Noble hop varieties include Hallertauer, Saaz, Spalt, and Tettnanger.
Nose
The overall aroma of a beer, best observed with short sniffs of a beer that has been poured into a wide rimmed glass.
  Original Gravity (o.g.)
A measure of wort's density at the beginning of fermentation, which will always be higher than 1 because solubles, such as maltose, are suspended in it. As the wort ferments, yeast converts maltose into alcohol and the gravity drops because alcohol is lighter that water. When a beer is done fermenting brewers take a final gravity reading or finishing gravity (f.g.).
Oxidation
A cardboardy, old bread, or cooked breakfast cereal aroma or flavor in beer that is the result of overexposure to light (common in clear- and green-bottled beers), the beer being exposed to oxygen for too long during fermentation, overpasteurization, or overboiling.
  Partial Mash
A term used to describe the brewing process in which both malted grist and malt extract are used.
Pasteurization
The process of gently heating beer after fermentation, which kills any remaining live yeast and bacteria, reducing the risk of contamination or spoilage. Heating of beer to 60-79°C/140-174°F to stabilize its microbiologically.
Peptidase
A proteolytic enzyme which breaks up small proteins in the endosperm to form amino acids.
pH
A negative logarithmic scale (1-14) that measures the degree of acidity or alkalinity of a solution for which a value of 7 represents neutrality. A value of 1 is most acidic, a value of 14 is most alkaline.
Phenol, Polyphenol
A hydroxyl derivative of an aromatic hydrocarbon that causes medicinal flavors and is involved in stalling reactions.
Phenolic
Any combination of medicinal, Band-Aid-like, plastic, Listerinelike, clovelike or electrical-firelike aroma or flavor in beer. It is usually caused by bacterial infection in beer.
Pin
A vessel for serving cask beer, equivalent to half of a firkin.
Pitch
To add yeast to wort in order to induce fermentation.
Plato, Degrees
Used in brewing industry to describe the amount of available extract as a weight or percentage of sugar in solution, in relation to specific gravity. Eg. 10 °Plato is equivalent to a specific gravity of 1.040. Used interchangably with Brix and Balling.
PPG (Points per Pound per Gallon)
The US homebrewers unit for total soluble extract of a malt, based on specific gravity. The unit describes the change in specific gravity (points) per pound of malt, when dissolved in a known volume of water (gallons). Can also be written as gallon*degrees per pound.
PPM (Parts per Million)
The abbreviation for parts per million and equivalent to milligrams per liter (mg/l). Most commonly used to express dissolved mineral concentrations in water.
Primary Fermentation
The initial fermentation activity marked by the evolution of carbon dioxide and Krausen. Most of the total attenuation occurs during this phase.
Priming
The method of adding a small amount of fermentable sugar and/or yeast prior to bottling to give the beer carbonation.
Processing Aids
Substances that is used in beer production that are not adjuncts, malt, hops, water or yeast. Processing aids come into contact with wort or beer but are removed before the beer is consumed (unlike additives which are left in). Many filtering agents or substances used to reduce chill haze are processing aids.
Protease
A proteolytic enzyme which breaks up large proteins in the endosperm that would cause haze in the beer.
Proteolysis
The degradation of proteins by proteolytic enzymes e.g. protease and peptidase.

 

  Racking
Siphoning, draining or pumping beer from one tank into another, leaving behind the trub, or the filling of kegs or other serving vessels.
Real Ale
The term used by CAMRA for traditional cask-conditioned ale.
Regional Brewery
Regional Brewery: A brewery with an annual beer production of between 15,000 and 2,000,000 barrels.
Regional Craft Brewery
Regional Craft Brewery: An independent regional brewery who has either an all malt flagship or has at least 50% of it's volume in either all malt beers or in beers which use adjuncts to enhance rather than lighten flavor.
Reinheitsgebot
The Bavarian beer purity law of 1516 that states that beer in Germany shall only be made with grain, hops, and water. Yeast, which was not fully understood at the time, is also a necessary ingredient in beer, and was added as the fourth ingredient in an ammended version of the Reinheitsgebot.
Rest
The period of time during which the mash is held at a pre-determined temperature in order to activate specific enzymes.
  Saccharification
The conversion of soluble starches to sugars via enzymatic action.
Saccharomyces cerevisiae
Genus and species name of yeasts used for brewing beer. In the past only ale yeasts were classified as Saccharomyces cerevisiae and lager yeasts were classified as Saccharomyces uvarum. Now both yeasts have been lumped together under the name Saccharomyces cerevisiae.
Saccharomyces uvarum
Formerly the genus and species name of lager yeast. Has been reclassified to Saccharomyces cerevisiae and is now classified as the same species as ale yeasts.
Sanitize
To reduce microbial contaminants to insignificant levels.
Secondary Fermentation
A period of settling and conditioning of the beer after primary fermentation and before bottling.
Sediment
The yeast and fermentation byproducts at the bottom of a bottle of conditioned beer - typically rich in vitamin B.
Serving Tank
The vessel from which beer is served.
Shelf Life
The number of days a beer will retain its peak drinkability. Packaged beer is generally best consumed fresh, with some exceptions among higher alcohol, non-pasteurized bottle conditioned beers, which can improve with some ageing.
Skunked
See light-struck.
Sparge
To spray grist with hot water to remove soluble sugars (maltose) from the malted barley. This takes place after the mash, in a tank fitted with a false bottom (lauter tank).
Specific Gravity (s.g.)
A measure of wort's density in relation to the density of water, which is given a value of 1 at 39.2 degrees F (4 degrees C). The addition of sugars (during mashing and sparging) raises specific gravity, while the coversion of sugars into alcohol (during fermentation) lowers specific gravity.
Sterilize
To eliminate all forms of life, especially microorganisms, either by chemical or physical means.
Sterols
Any of various solid steroid alcohols widely distributed in plant and animal lipids.
Striking
Adding hot water to grist to start the mash process.
Sucrose
This disaccharide consists of a fructose molecule joined with a glucose molecule. It is most readily available as cane sugar. Sucrose is generally not used in brewing, as it will result in a cidery aroma.
Sulfur Compounds
Compounds which produce a sulfury, rotten egg, burnt rubber, or striking match aroma in a beer which can form during fermentation under certain conditions.
  Tannins
Astringent polyphenol compounds that can cause haze and/or join with large proteins to precipitate them from solution. Tannins are most commonly found in the grain husks and hop cone material.
Trappist
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.
Trub
The sediment at the bottom of the fermenter consisting of hot and cold break material, hop bits, and dead yeast.
Tun
Any large vessels used in brewing.
  Ullage
Beer that is stale or infected and therefore cannot be sold. Often returned by the publican to the brewery.
  Vinous
Wine-like. Typically referred to beer that has the off-flavor of an old opened bottle of wine caused by the reaction of esters and alcohols with acids.
  Wet Hopping
A term used to describe the addition of freshly picked (not dehydrated) hops. Wet-hopped, or "harvest" beers are brewed by a select few breweries once a year, immediately following the hop harvest in early fall.
Wort
The sweet liquid produced in the brewing process by mashing malted barley and water. Beer is called "wort" before yeast is added. The malt-sugar solution that is boiled prior to fermentation. (Pronounced "wirt" - rhymes with dirt).
  Yeast
A single-cell, micro-organism of the fungus family, which consumes fermentable sugars in the wort and produces alcohol, carbon dioxide, flavors and aromas in beer. There are many yeast strains used in brewing, each with unique characteristics. The two primary yeast varieties are ale yeast, which ferments at warmer temperatures, and lager yeast, which prefers cooler temperatures.
Yeasty
A yeast-like flavor often derived from beer sitting on yeast too long during fermentation.

 

  Zymurgy
The science or study of brewing and fermentation.

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