Beer Glossary

n. An ingredient used in making beer other than the four permitted by the German Reinheitsgebot law: malted barley, hops, water and yeast.

n. A small apparatus, usually partially filled with water, that is inserted into a hole in the top of a closed fermenting vessel to allow CO₂ from the fermentation process to escape without allowing oxygen or foul-tasting microorganisms in. CO₂ escapes an airlock by bubbling through its contained water; the rate at which fermentation is proceeding can be estimated by the rapidity of an airlock's bubbling.

n. A wheatlike grain used in the making of beer. See also malt.

n. Libation of the gods. An alcoholic drink that has been around since the time of the Ancient Egyptians, and (usually) consists of four ingredients: malted barley, hops, water and yeast. During the Middle Ages, beer was frequently consumed in lieu of water, as public water sanitation was lacking or nonexistent. No known human pathogens can survive the brewing process, so making one's own beer is very safe.

v. To bring a liquid to a temperature and pressure at which it begins to evaporate. For pure water at sea level, this occurs at 212° F (100° C). Boiling occurs at lower temperatures at lower pressure, so at higher elevation, boiling requires the addition of less heat.

Boiling serves a few purposes when making beer. Preeminent is the isomerization (changing of the structure of molecules, in this case making them water-soluble) of the alpha and beta bittering acids from hops -- the longer hops are boiled (up to 75 minutes or so), the more isomerization occurs, and the more strongly hop bitterness will be perceived in the final beer. A typical hopping schedule will include an addition of hops at the start of a 60-minute boil for bitterness only, another addition at the half-hour mark for hop flavoring, and another at the 50 or 55-minute mark for hop aroma.

Boiling is also important for precipitating certain undesirable proteins from the grain solution; the hot break occurs during first five or ten minutes of a boil, and the cold break occurs while rapidly cooling the boiled wort mixture.

The sterilizing benefits of a long boil are also (usually) appreciated in beer making.

n. Precipitation of undesired proteins within a wort. The terms hot break and cold break are used to describe both the event and the material substance of this precipitation. Hot break usually occurs within the first ten minutes of a wort boil, and looks like pea-sized flakes or granules floating in the wort. Cold break occurs during the cooling of a wort from boiling to yeast-pitching temperature, and the precipitation is more thorough the more rapidly the temperature is lowered by the brewer.

v. For the purposes of this website, to make beer. Beer brewing is a process that encompasses the following steps: mashing, lautering, boiling and fermentation.

n. slang A serving of beer, or brand of beer.

n. CO₂ is a colorless gas that is harmful to human beings when breathed in concentrations of 10% or higher, leading to asphyxiation. CO₂ is also a normal byproduct of human respiration and yeast fermentation. When CO₂ is dissolved into beer, either as part of the fermentation process or by forced pumping, it is called carbonation, and results in the "head" of foam that is characteristic of a well-poured brew.

n. A container, typically used in stand-up water coolers. Glass carboys are frequently used, when stood on their flat ends, as fermentation vessels for home-brewed beer.

n. To allow beer to sit undisturbed while fermentation occurs and undesirable materials settle out of the beer as sediment. Frequently beer is racked into a secondary fermentation vessel before clarifying, so the beer is not in long-term contact with its trub.

n. The biological process by which yeast consumes carbohydrates and produces the byproducts carbon dioxide (CO₂) and alcohol. Transforms wort into beer.

n. The prevailing spice used in the brewing of beer. Hops are the conelike flower of a vine, species humulus lupulus, that is a member of the cannabis family. Hop flowers contain small yellow "lupulin glands" that secrete bitter acids and resins which are greatly prized in beer as a counterpoint to the sweet taste of malt. Hops also act as a preservative in beer, and contribute certain proteins to the mixture that aid in the retention of a head of foam. Hops have only been used widely in beer for approximately 500 years.

v. To strain spent grain from the water into which the grain's sugars have been extracted by the mashing process.

v. malting The process of soaking, then drying grains like wheat or barley. This begins, then halts the germination process in the grains, which suspends the enzymatic process of converting starches in the grain seeds to sugars. This renders the grains optimal for mashing and conversion into beer.

n. A quantity of grain that has undergone the malting process.

v. To soak malted grains in water at temperatures that favor enzymatic action, usually for the purpose of converting long carbohydrate chains to smaller chains of simple sugars that are optimal for fermentation by yeast, and extracting them into the water. The grains are then typically strained from the mash by lautering.

n. A quantity of water and malted grains in the process of being mashed.

v. To introduce a live yeast culture into cooled wort to begin the fermentation process in order to produce beer.

n. Sugar (typically a solution of either dry malt extract or simple corn sugar) added to fermented beer before bottling. Provides additional fermentable material for the yeast that remains in suspension, so that carbonation can occur naturally in the sealed environment of the bottles.

Care must be taken not to add too much priming sugar, or the yeast will produce excessive CO₂, and the beer will be unpleasantly over-carbonated and can even burst its bottles.

v. To move beer from one vessel to another during the fermentation process. Typically done to separate a beer from its trub. Care must be taken not to splash or cause bubbling in the beer when racking (introducing excess oxygen to beer after fermentation begins can cause off flavors), so a gentle gravity-powered siphon is usually used.

n. ("rine' - heights - geh - boat") A German law, often called the "German beer purity law" in America, enacted in 1516, that mandates that beer contain only these four ingredients: malted barley, hops, water and yeast. The provision allowing yeast was added after Louis Pasteur's work proved yeast's existence and necessity to the fermentation process. The Reinheitsgebot was changed from a law to an industry standard when Germany joined the European Union.

v. To run hot (approximately 170° F) water through nearly-spent grains that have been mashed, in order to extract further sugars from them.

n. ("troob") Sediment, mostly dead or quiescent yeast, that collects in the bottom of a beer fermentation vessel. Though trub in beer is considered harmless for periods of two weeks or less, beer can develop off flavors if the beer's living yeast, when starved for nourishment, begins to consume the trub. To avoid these off flavors, a brewer will frequently rack beer to a secondary fermentation vessel if the beer needs to clarify for more than a week or two.

n. A container used for mashing and/or lautering, i.e., mash tun or lauter tun.

n. Dihydrogen oxide, or H₂O. Water is an important ingredient in beer, and its most essential quality is cleanliness. If water is pleasurable to drink, good beer can be made from it.

Beyond simple potability, water composition can be very important to certain styles of beer. The soft (mineral-poor) water of the Czech city of Plzn, for example, is an essential ingredient of the famous Pilsener Urquell, and would be missed if changed. The peculiar mineral composition of water from towns like Burton, England are also frequently copied by home brewers making authentic beers for a region.

n. Water in which sugars have been collected from malted grain via the mashing and sparging processes, and possibly boiled with hops.

n. Unicellular fungi that are introduced to a wort, fermenting it into beer.

Yeast comes in two major varieties for the making of beer: ale yeast and lager yeast. Ale yeast tends to do its fermentation at the top of the fermentation vessel, and prefer temperatures between 60° F and 75° F. Lager yeast gravitates toward the bottom of its fermentation vessel, and works best between 40° F and 55° F.

Beers made from ale yeast strains tend to have more complex characters and darker color, while beers made from lager yeast typically have a "cleaner," "crisper" taste and lighter color.

n. The branch of chemistry concerned with fermentation.