Brewers' Glossary

Brewers’ Glossary

Acrospire. The embryonic barley plant which grows inside the husk during germination.

Adjunct. Any unmalted grain used as a source of sugar in brewing.

Ale. Beer made with ale yeast (Saccharomyces cerevesia), often with a fruity aroma caused by fermenting at warmer temperatures.

Alpha Acid. A sticky, bitter resin found in hops, which imparts bitterness to the finished beer.

Amylase. Any enzyme which breaks the bonds that hold starch molecules together.

Appearance. The overall look of a particular beer sample.

Aroma. The smell produced by the raw ingredients, not the bittering compounds, in beer.

Aroma Hops. Hops used to impart aroma, as opposed to bitterness, in beer.

Aromatic Hops. Hops varieties known for their fine aroma and flavoring properties. Also known as Noble Hops.

Attenuation. The drop in specific gravity that takes place as the wort ferments.

Autolysis. A process in which starving yeast cells feed on each other by excreting enzymes; causes an unpleasant, rubbery stench in beer.

Bacteria. Primitive microorganisms smaller than yeast. Certain types of bacteria can infect wort and beer and result in off-flavors.

Beta Acid. A soft, bitter hop resin; harsher in flavor than alpha acid but almost insoluble at normal wort pH values.

Bittering Hops. Hops added to the wort early in the boil to cause bitterness.

Body. The sensation of fullness or viscosity in the mouth, imparted by malt proteins in beer.

Bottle-conditioned. Carbonated by a second fermentation that takes place in the bottle as a result of yeast left in the mixture after bottling.

Bottle-fermenting. Describes yeast that flocculates late in the fermentation and sinks to the bottom of the fermenter.

Break. Visible particles of protein and other matter that form in wort during boiling and cooling.

Brewing. The process of making wort, boiling it with hops and fermenting it into beer.

Carbonation. The process of dissolving carbon dioxide gas in a liquid, such as beer.

Cold Break. The flocculation of protein and polyphenol molecules during wort cooling.

Chill Haze. Tiny particles that form in beer when it is chilled and make the beer appear cloudy. An undesirable characteristic.

Clarifier. A substance used to remove or prevent chill haze.

Conversion. The process in which natural malt enzymes change grain starch into sugar during the mash.

Decoction. A method of mashing which boosts temperature from one step to the next by removing a portion of the mash, boiling it, and returning it to the main brew kettle.

Dextrins. Complex carbohydrates that contribute to the mouthfeel of beer.

Diacetyl. A compound that gives beer a butterscotch-like taste.

Diastatic Power. A measure of the total amylase content of a given sample of malt; usually expressed in degrees Lintner.

Dimethyl Sulfide (DMS). A powerful aromatic compound which imparts a sweet creamed corn scent to lager mashes. In finished beer it imparts a malty quality, or, at higher levels, the taste of cooked vegetables.

Dry. Opposite of sweet. In a dry beer, bitterness predominates over sweetness.

Endosperm. The nonliving part of the barley grain which contains starch and protein to feed the growing acrospire.

Enzyme. A complex protein which has the ability to form or break a particular chemical bond.

Esters. A class of compounds formed by joining an alcohol and an acid; many have powerful fruity aromas.

F. Abbreviation for Fahrenheit, the scale used to measure temperature in the United States.

Fermentation. The metabolism of sugar into carbon dioxide and alcohol, performed by yeast and some bacteria.

Fermenter. A vessel used to contain wort during fermentation.

Finings. Any substances used to help yeast flocculate and settle out after fermentation.

Finishing Hops. Hops added to the wort late in the boil, to impart a hoppy aroma rather than bitterness.

Flocculation. The process in which yeast cells clump together to form large visible particles, which can then fall out of suspension.

Grist. The crushed malts and adjuncts that are mixed with hot water to form the mash.

Haze. An undesirable cloudiness in beer, caused by tiny particles that form in the beer during chilling. See also ‘Chill Haze’.

High-Alpha Hops. Hops varieties bred primarily for maximum bittering power. These are most useful as bittering hops.

Hops. The cones or flowers of the female Humulus lupulus plant. They may be dried whole hops or may be used after being dried into pellets.

Hot Break. The flocculation of protein and polyphenol molecules during boiling.

IBU. International Bittering Units. A standard measure of the hop content in beer.

Hops

Infection. The growth of any microorganism in wort or beer, except for the the brewer’s yeast that was deliberately added. Most infections harm the flavor of the finished product.

Infusion. Single vessel heating used to break down the stored starches within the grain into fermentable sugars.

Isomertization. The extraction of hop bitterness.

Lactic Acid. A tart acid, produced by yeast and by certain types of bacteria that infect beer.

Lager. Beer that is fermented cool using lager yeast (Saccharomyces carlsbergensis) and stored cold for a period of weeks in order to give it a clean smooth flavor. From the the German verb meaning "to store".

Lauter Tun. A vessel used to strain the sweet liquor or wort off the spent grains after mashing.

Lovibond. The scale, in degrees, on which American brewers measure the color of malt, wort and occasionally the color of beer. Lager

Lupulin Glands. The tiny yellow sacs found at the base of the petals of the hop cone. They contain the alpha acids, beta acids and hop oils.

Malt. Barley or other grain which has been soaked with water, allowed to sprout, and then dried. Sprouting allows development of the enzymes that bring about starch conversion in the mash.

Mash. 1.(verb) To make a thick mixture of hot water with crushed malt and in some cases, adjuncts, in which the grain starches are converted to sugar. 2. (noun) The mixture described in definition 1.

Mouth feel. The sensation of fullness in the mouth created by dextrins and proteins in the beer. See also Body.

Original Gravity. The specific gravity of the wort before fermentation begins.

Oxidation. Any chemical reaction involving oxygen. It gives beer an undesirable flavor.

pH. The measure of acidity of alkalinity. 7 is the neutral point of the scales, with lower values being acid, and higher values alkaline.

Phenolic. Any compound based on a ring of six carbon atoms joined by alternating single and double bonds. The so-called tannins contained in grain husks are phenolic in nature, as are the soft hop resins, also called alpha and beta acids.

Polyphenols. Complex compounds based on two or more phenolic rings joined together.

Protein. Any complex organic compound containing nitrogen.

Rack. To transfer beer from one vessel to another, leaving the sediment behind.

Reinheitsgebot. German Purity Law allowing only water, malted barley, malted wheat, hops and yeast to be used in the brewing of beer.

Respiration. The process in which living things oxidize sugar in order to obtain energy.

Sanitize. To make clean and free of microorganisms.

Sparge. To rinse the grain bed in the lauter tun with hot water in order to recover the residual sugar.

Specific Gravity. A measure of density. This measurement compares the heaviness of a given volume of beer to pure water. Malt sugar increases the specific gravity of wort and fermentation, by removing the sugars, lowers it. The scale is absolute, meaning a specific gravity of 1.050 means the beer weighs 1.050 times as much as an equal volume of water.

SRM. Standard Research Method. A standard measurement of the color range of a specific beer or style of beer.

Strain. Yeast which shares a common genetic makeup and specific traits, such as flavoring properties.

Style. The whole sum of flavor and other sensory characteristics by which individual beers may be placed in categories for purposes of comparison, tasting and judging. Beers of the same style have the same general flavor profile.

Terminal Gravity. The specific gravity of beer after fermentation is completed. Also called final gravity.

Top-fermenting. Describes yeast that flocculates relatively early in the fermentation and is carried up into the head of foam in the wort by carbon dioxide bubbles.

Wild Yeast. Any yeast that is introduced accidentally into wort or beer from the environment.

Wort. A sugar solution derived from grain by mashing and sparging.

Yeast. A relatively large and complex single-celled microorganism. It thrives on sugar, which it ferments, and also requires oxygen and nutrients in order to grow.