Knowledge base

Adhumulone: Typically constitutes ~15% of alpha acids. Oxidizes into 2-methylbutryic acid which has an odor remniscent of Roquefort cheese

Adjuncts: Ingredients that are not fermentable (malt, sugar, syrup), hops or a yeast. Usually spices such as coriander seeds, or additives such as Irish moss.

Adlupulone: Tertiary Beta Acid. ~10-15% of beta acids.

1-Propanol (Alcohol): Alcohol. A primary alcohol formed natulally in small quantities during fermentation. Aroma: sharp musty odor, like rubbing alcohol.

Alcohol By Volume (ABV): The percentage of a fluid that is alcohol.

Isobutanol (Alcohol): Alcohol. A primary alcohol formed natulally in small quantities during fermentation. Aroma: sweet odor.

Acetaldehyde: Flavour/aroma: green apples. Produced during fermentation (as an intermediary between glucose and ethanol) and when ethanol is oxidised. Can be metabolised into acetic acid by aerobic bacteria.

Alkaline Cleaners: Chemclean, PBW, Chemipro Wash

α-Amylase (Alpha-Amylase): α-Amylase is an enzyme that splits starch into maltose during a mash.

Esters (fruit esters): Flavour/aroma: fruit, banana.

Attenuation: The percentage of sugar a yeast will consume (and produce alcohol and CO2).

Acetobacter: Bacteria. Infection, smell/taste of nail polish remover or vinegar.

Lactobacillus: Bacteria. Lactobacilli, especially L. casei and L. brevis, are some of the most common beer spoilage organisms. They are, however, essential to the production of sour beers such as Belgian lambics and American wild ales, giving the beer a distinct tart flavor.

Pediococcus: Bacteria. Pediococcus is, along with other lactic acid bacteria such as Leuconostoc and Lactobacillus, responsible for the fermentation of cabbage, making it sauerkraut. In this process, the sugars in fresh cabbage are fermented to lactic acid, which gives sauerkraut a sour flavour and good keeping qualities. Pediococcus bacteria are usually considered contaminants of beer and wine, although their presence is sometimes desired in beer styles such as lambic and Berliner Weisse. Certain Pediococcus isolates produce diacetyl which gives a buttery or butterscotch aroma.

Base Malt: A malt containing both a lot of starch and enzymes that convert starches to fermentable sugars during a mash.

Bottle Bomb: A bottle that was either tapped with too high residual sugars, or was infected by a yeast or bacteria that can digest "non-fermentable" sugars. The excess pressure leads to the bottles exploding, hence the name "bottle bomb".

Cohumulone: Secondary Alpha Acid. ~20%-50% Generally found in lower percentages. Provides a harsh bitterness, hence often less desirable.

Colors in brewing: <p>Colors in brewing is usually measured in three standards: srm, ebc and °L.</p><ul><li><strong>Standard Reference Method (srm)</strong> is the standard measurement used in the United States.</li><li><strong>European Brewer's Convention (ebc)</strong> is the standard measurement used in Europe (and internally in Microbrew.it).</li><li><strong>lovibond (°L)</strong> is an older color measurement standard based on a set of colored glass. Often used to measure the color of malts.</li></ul>

Colupulone: Secondary Beta Acid. ~20-55% of beta acids.

4EG Compound: 4‑ethylguaiacol. A compound that most people perceive as phenolic bacon, spice, clove and smoky aromas.

4VG Compound: 4‑vinylguaiacol. A compound that most people perceive as phenolic spice and clove flavors.

4VP Compound: 4‑vinylphenol. A compound that most people perceive as phenolic barnyard, medicinal and band-aid aromas.

4VS Compound: 4-vinylsyringol. A compound that most people perceive as phenolic smoked, burned and tobacco aromas.

Conical Fermenter: A fermenter that has a conical shape, usually stainless steel. The conical shape means sediments have a lower surface area of contact with the beer. Many conical fermenters has a valve at the bottom, letting you remove sediments and collect flocculated yeast.

Diastatic Power: The ability of malt to convert starch to sugar. Measures amylase enzymes. In the US usually measured in degrees Lintner, in Europe in degrees °Windisch-Kolback.

Dimethyl sulfide (DMS): Off-flavour. Sulfur: dimethyl sulfide or DMS. Flavour/aroma of Corn. Usually caused by using very pale malts (like pilsner malt) that contain high levels of SMM (the precursor of DMS), cooling the boil too slowly combined with too slow fermentation. Can also be caused by bacteria, but then you usually get different flavours such as cabbage, celery, or even shrimp.

Dip Hopping: Adding hops after wort cooling, before pitching yeast.

Dry Hopping: The act of adding hops to the fermentation, conditioning (secondary) or serving vessel. Has the effect of extracting hop essential oils without isomerizing the alpha acids, leading to an (almost) pure aroma extraction without adding bitterness.

ebc: European Brewers Convention. Measure of color used in Europe.

Ethyl Acetate (Ester): Ester. Formed during fermentation. Aroma: Pear, fruity, sweet, solvent.

Ethyl Hexanode (Ester): Ester. Formed during fermentation. Aroma: fruity, apple peel.

Ethyl Octanoate (Ester): Ester. Formed during fermentation. Aroma: strong fruity, apricoty, flowery odor.

Isoamyl Acetate (Ester): Ester. Formed during fermentation. Aroma: banana, pear.

Final Gravity (FG): Final Gravity: A measure of the sugar contents (density) of the finished beer. Measured in Specific Gravity (SG). A measure of fermentation efficiency. Used together with OG to calculate ABV.

Fermenter: A vessel that fermentation occurs in. Usually a bucket, glass container or stainless steel container.

Flocculation: A yeast's tendency to clump up after fermentation, clearing up a beer. High flocculation means a clearer beer.

AWA1 Gene: Gene in ale yeast that aids foam. Awa is Japanese for bubbles. Hydrophopic cell surface mannoproteins that stick to bubble surface and stabilises foam.

CFG1 Gene: Carlsbergensis Foaming Gene 1. Gene in lager yeast that aids foam.

FDC1 Gene: Gene in brewers' yeast responsible for enabling an enzyme that produces the 4VG compound which most people perceive as phenolic spice and clove flavors.

HZY1 Gene: Gene responsible for creating hazyness. Prevalent in yeast strains used to ferment Hazy IPAs.

POF+: POF+ (positive for phenolic off-flavor) phenolic-producing yeast.

STA-1 gene: Strains of yeast with this gene may have the ability to metabolize dextrins over time (i.e becoming diastaticus), resulting in higher than expected attenuation.

Grain Bill: aka mash bill. The mash ingredients used to produce wort.

Humulone: Primary Alpha Acid. ~20%-50% Primary aa found in most hops. Known for a soft bitter flavor that is far from harsh.

Humulones: Scientific name of Alpha Acids.

Irish Moss: Clearing agent. Added to boil, ~15 min before end, to make proteins clump together.

Kolbach Index: The Kolbach index is the relation of the soluble protein percentage on the total nitrogen percentage. The Kolbach index permits to encode the chemical disintegration of the malt. The scale of values is between 29 and 45%: <br />- > 45 excessive disintegration and it can cause disturbances in the beer <br />- > 41 very good disintegration <br />- between 35 and 41 good disintegration <br />- < 35 insufficient disintegration <br />The brewer designates in the specification the fork of tolerance of the Kolbach index.

Kreusen: Foamy layer formed on top of actively fermenting beer.

Lintner: Scale used to measure the diastatic power (conversion power from starch to sugar) of malts. Often used in the US. Measured in °L.

Lipids: Oily or greasy organic compounds found in living cells. Found in malts. Oxidised lipids leads to a wet cardboard aroma.

lovibond: Color scale created by Joseph lovibond in the 1860s, measured in degrees lovibond (°L). A set of colored glass plates that color is compared to (lower means lighter). Often used to specify grain/malt color.

Lupulone: Primary Beta Acid. ~30-55% of beta acids

Lupulones: Scientific name of Beta Acids.

Mash: Liquid containing malt.

Melanoidin: Melanoidins are brown, high molecular weight heterogeneous polymers that are formed when sugars and amino acids combine at high temperatures and low water activity. Melanoidins are commonly present in foods that have undergone some form of non-enzymatic browning, such as barley malts and coffee.

OG: Original Gravity: A Measure of the sugar contents (density) of the wort. Measured in Specific Gravity (SG). A measure of mash efficiency. Used together with FG to calculate ABV.

Phenolic Off-Flavor (POF) gene: Yeast that carry the POF gene create phenols such as 4-Vinyl Guaiacol (4VG), which are known for creating off-flavors.

LPT1 Protein: Protein from malt that aids foam formation.

Protein Z: Protein that aids foam retention (Proteins Z4 and Z7).

Specific Gravity (SG): Specific Gravity: A measure of density of a fluid, measured with a hydrometer. Alternative measures are Plato and Brix.

Single Malt and Single Hop (SMASH): A beer brewed using a single malt in its grain bill and a single hop for both bittering and aroma.

S-methylmethionine (SMM): Produced during the germination of barley, a key step in malting. All but the very lightest malts have most of their SMM driven away during kilning, but lightly kilned malts hold on to as much as eight times as much SMM as standard pale malt. Breaks down into DMS when heated (mash, boil), but boiling actually drives much of it away through evaporation.

Standard Reference Method (srm): Measure of color used in the US.

Specialty Malts: Malt that has been treated somehow. Contributes color, flavor and aromas. Low enzyme and lower starch contents than base malts.

Trub: A layer of segments formed at the bottom of wort when cooling the liquid.

2,3 Pentanedione (VKD): Flavour/aroma: honey, buttery, cheesy, sweet, nutty, fruity, creamy, caramel. Also known as Acetylpropionyl.

Diacetyl (VKD): Flavour/aroma: artificial sweet butter, caramel, butterscotch. Also known as 2,3 butanedione. Caused by fermentation or bacteria. Caused by high fermentation temperatures, or too short conditioning. Can also occur in packaged beer if stored too warm.

Vicinal Diketones (VKD): Group of flavor components, including diacetyl (butter, caramel) and 2,3 pentanediona (honey)

Wet Hopping: The act of using un-kilned hops (meaning they have far more moisture) as opposed to dried hops.

Whirlpool: A way of chilling the wort using a pump and a spiral chiller before adding yeast.

Windisch-Kolbach: Scale used to measure the diastatic power (conversion power from starch to sugar) of malts. Often used in Europe. Measured in °WK.

Wort: Beer before yeast is added. After boiling the mash you have wort.