Knowledge Base:  
Homebrew Glossary
Last Updated: 03/11/2014


American Society of Brewing Chemists is a professional organization that specializes in establishing true standards and testing methods for brewing materials and processes.


The beginnings of a plant shoot in germinating barley.


A non-enzymatic fermentable.  These include unmalted cereal such as flaked barley or corn, syrups and refined sugars.


To mix air into a solution.  Used to provide oxygen for yeast once wort is cooled and before primary fermentation.


A process that utilizes oxygen.


A simple oneway device that attaches to the fermenter to allow CO2 to escape while not allowing contaminated outside air to enter.


A chemical precursor to alcohol.  Alcohol can be oxidized to aldehyde and creates off-flavors.


A beer style that utilizes top fermenting yeast with a relatively short room temperature fermentation.

Aleurone Layer

A living sheath that surrounds the endosperm of a barley kernel that contains enzymes.


The zone of pH between 7 and 14.  Often present in water with bicarbonate ions - HCO3

Alpha Acid

Alpha Acid Units (AAU) - A home brewing measurement of hops.  Equal to the weight in ounces multiplied by the percent of alpha acids.

Amino Acids

Vital building block in the construction of proteins, composed of an organic acid containing an amine group - NH2


An enzyme group that converts starch into sugar.  This consists primarily of alpha and beta amylase.  Can also be referenced as diastatic enzyme.


A branched starch chain found in the endosperm of barley.  It can be considered to be comprised of amylose.


A straight chain starch molecule found in the endosperm of barley.


A process that functions without the presence or use of oxygen.

Apparent Attenuation

The percent reduction in specific gravity due to fermentation. AA% = OG-FG/OG


The degree of sugar conversion to alcohol and CO2


When yeast exhaust the their available nutrients and die the cell wall ruptures and produces off-flavors.


If you need this defined or spelled out for you - we are in serious trouble.  However, the technical definition is a beverage made by fermenting a wort made from malted barley and seasoned with hops.


A hard organic scale the deposits on fermentation equipment.  Comprised of calcium oxalate.

Beta Acid


A colorless crystalline vitamin from the B complex.  Found in yeast, liver, and egg yolks.


A type of airlock that utilizes a tube from the fermenter into a buck or bottle of water that allows for the CO2 gases to escape but does not allow the ambient air to enter the fermenter.  These tubes also allow excess fermentation material to escape with ease and not clog traditional airlock mechanisms.

Bottle Conditioned


A chemical that helps stabilize the pH of a solution.  This can happen either by disassociation or reassociation within the liquid mixture.  Salt is a common buffer agent.






A chemical mirror of the starch molecule.  This molecule cannot be broken down by starch enzymes just as cellulose enzymes cannot break down starch molecules.


A Cicerone is a certified beer professional with a deep and well-rounded knowledge of beer and beer service as well as competence in assessing beer quality and identity by taste.  Similar to a wine Sommelier, but a Cicerone is for experts who love and are passionate about beer.

Cold Break

Proteins that coagulate and fall out of solution when the wort is rapidly cooled prior to pitching your yeast for the primary fermentation.


A term for secondary fermentation in which yeast refine the flavors of the beer.   Bottle conditioning refers to the level of carbonation and quality of mouthfeel of a beer during judging.


A method of mashing grain where temperature rests are achieved by boiling a part of the mash and returning it to the mash tun.


A complex sugar that is left over from diastatic enzyme action on starch.


A common byproduct of fermentation that has a slight buttery or butterscotch aroma and flavor.  Diacetyl is normally cleaned up by the yeast during the second fermentation.

Diastatic Power

The diastatic enzyme potential that a given malt contains.

Dimethyl Sulfide (DMS)

A flavor compound that is desirable in low amounts in lagers.  When present in too high amounts the taste can be similar to cooked vegetables such as corn or cabbage.

Dry Hopping

Dry Malt Extract (DME)


The nutrient portion of a seed that consists of carbohydrates, proteins, and lipids.


Protein based catalyst that effect biochemical reactions.


Fruit aroma that is formed from yeast in the production of alcohol.


The type of alcohol that is in beer from the yeast conversion of malt-sugar.

European Bitterness Units (EBU)

A bitterness measurement.  Is equivalent to IBU.

European Brewing Congress (EBC)

A unit of color based on optical spectophotometry to measure the absorbance of a specific wavelength of light - 430 nonometers through a standard size sample.


The soluble material derived from barley malts and various adjusts.

Fatty Acid


The conversion of sugars into alcohol.  Typically conducted in three distinct phases, which include: adaptation, primary and secondary.

Final Gravity

Fine Grind Dry Basis (FGDB) - A measure of the total soluble extract for a particular malt in a perfect laboratory mash and lauter.  Used as a basis for ppg and HWE.



A process of becoming clumped together.  Yeast perform this and settle out of solution at the bottom of the fermenters.

Force Carbonating

Fructose - Simple fruit sugar.

Fusel Alcohol


Franco-Belgian patron saints of beer - Gambrinus is a legendary European culture hero celebrated as an icon of beer, brewing, joviality, and joie ... In reality there was no official church sainted by the name Gambrinus.


The process of making starch soluble in water by either heat or a combination of heat and enzyme action.



Common type of sugar.  Also known as dextrose, corn sugar, and blood sugar.


Describes the concentration or density of sugar in a liquid (namely wort in the beer making process).  Water has a specific gravity of 1.0 at 59F.  Worts typically have a gravity range from 1.035 - 1.055 before fermentation.  This initial gravity before fermentation begins is also referred to as Original Gravity and is often abbreviated with OG.


Crushed malt.




Hop vines are grown from rhizomes in cooler climates.  They can grow as tall as 10-12+ feet.  The cone like flowers are harvested in the fall when they turn a lighter/brighter green tone.  Hops are available in a variety formats, such as: pellet, leaf, plugs and whole cones.  Hops are what deliver the very distinct flavor and aroma properties to beer.  Newer varieties are constantly appearing on the market which give the the home brewer a great selection for producing a wide range of tastes and aromas.

Hot Break

Are proteins that coagulate and fall out of solution during the boil phase of home brewing.

Hot Water Extract (HWE)

Hydrolysis -


A process in mashing where heating is accomplished with the addition(s) of boiling water.

International Bitter Units or IBU

A precise method of measuring hops.  Equal to the AAU multiplied by factors for percent utilization, wort volume, and gravity.  An IBU is defined as 1 milligram of isomerized alpha acid per liter of beer.

Invert Sugar

Irish Moss

A emulsifier that aids break material to form at the end of the boil phase resulting in a clearer brew.



Pronounced - kroy-zen - Refers to the foamy head that builds on top of beer during fermentation. It can also be used as an advanced form of priming whereby a small amount of yeast is extracted from a secondary fermentation to help instigate a fermentation process in a newer batch of beer entering its primary stage of fermentation. G. Heileman Brewing Company from LaCrosse Wisconsin was famous for this type of fermentation.

Lactic Acid

A sour or tart acid which is produced by bacterial fermentation.  A non-desirable trait in most beers it is desired in lambric and Berliner weisse styles.


Ingredient in milk that is commonly used in stouts to produce milk stouts.  It is considered an unfermentable sugar.

Lag Time

The period of adaptation and rapid aerobic growth of yeast upon pitching to the wort.  Typical lag time lasts from 2-12 hours.


A beer style where fermentation is typically held at the bottom of the fermentation vessel and works at a much lower tempertature.  Lager beers are usually higher in clarity, have a maltier flavor and lack many of the esters that are present in other beer styles.


To strain or separate.



Liquid Malt Extract (LME)

Liters Degrees per Kilogram


A malt color measurement.

Lupulin Glands

Maillard Reaction





The hot water steeping process that promotes enzymatic breakdown of the grain (or grist) into a soluble fermentable sugars.


Also known as wood alcohol and is not produced in any large amounts from the beer making process.


Parts per Million (ppm)




In brewing circles is a term used when yeast is added to the fermenter.

Points per Pound pre Gallon (PPG)

Polyphenol -

Primary Fermentation

The first and often vigorous fermentation phase which produces carbon dioxide and often kraeusen.  It is during the primary fermentation phase when the total attenuation occurs.


Is the method of adding additional fermentable sugar just prior to bottling.  This added sugar is what the yeast will bottle condition the beer and add the characteristic carbonation to the beer.




Is the careful siphoning of beer from one vessel to another which attempts to leave behind the spent yeast or turb that sits at the bottom of the originating vessel.

Racking Cane

is a long rigid plastic or stainless tube that helps aid the siphoning process.



To reduce microbial contaminants to insignificant and harmless levels.

Secondary Fermentation

The period of settling and conditioning of the beer between the primary fermentation phase and bottling.  Brewers often rack and transfer their elixir from their primary fermentor (often a simple bucket) to a traditional glass or plastic carboy for this phase.  This helps leave behind a fair amount of spent yeast and can significantly improve the overall quality of the brew as the liquid does not have prolonged contact with the dead yeast sediment.


Term for rinsing the grain during lautering by sprinkling water over the gain bed.

Specific Gravity / Balling / Brix / Plato

Are all units used in measuring the amount of sugar in a liquid solution.  10 degrees Plato == Specific Gravity of 1.040

Standard Reference Method (SRM)

Used to provide a color reference standard by the American Society of Brewing Chemists.


To eliminate all forms of life and microorganisms, either by chemical or heat means,



Strike Heat



Turb / Trub / Troob

The sediment at the bottom of the fermenter consisting of various hot and cold break material, bits of hop, and dead yeast cells.


The space occupied between the beer surface and top of the container.  Also known as headspace.


Sweet sugary liquid that comes from mashing.  Unfermented beer.

Wort / Wert / Wart

The malt-sugar solution that is boiled prior to fermentation. The wort before the boil is referred to as the Sweet Wort, after the boil and hops added it is referred to as the Bitter Wort.


The miracle maker that is responsible for converting simple sugars into alcohol.  They are a single celled micro organism from the fungi kingdom.


The science of brewing and fermenting.

Was this article helpful?