Glossary of Homebrew Terminology

Most hobbies and dedicated communities have a range of terms and abbreviations that are unique to them and brewing beer at home is no different.

Below is a glossary of homebrew terminology covering some of the more common terms and acronyms used through homebrewing that will help you with understanding things a bit better.
This is far from being a comprehensive list but if you are aware of these terms as a minimum, you should be able to hold a conversation with just about anyone.



Any fermentable ingredient added through the creation of wort. These are added for a variety of reasons including to reduce the final cost, increase alcohol volume, change color or improve the body of the final beer.

Alpha Acid

One of the resins found in hops. The bitterness in beer is caused by the conversion of these through the process of boiling the hops in wort.


The conversion of fermentable sugars in wort (by yeast) into alcohol and carbon dioxide gas.

Final Gravity (FG)

The Specific Gravity of the beer as measured when the fermentation process is complete


The point at the end of the hops boil where the flame is extinguished. Some homebrew recipes will call for the addition of hops at this point in order to add aroma only (i.e. no bittering)


The crushed malt and other fermentables mixed with hot water in preparation for mashing.

International Bitterness Unit (IBU)

The unit of measurement used in making beer to express bitterness. This is measured as milligrams of iso-alpha-acid (created when hops are boiled) per liter of beer

Krausen (pronounced kroy’-zen)

The layer of foam that appears on the surface of the wort during fermentation.


Grain (normally barley) soaked in water, germinated and then kilned to stop the growth of the grain and to reduce moisture. This modifies the grain so that sugars can be extracted by mashing.

Malt Extract

Concentrated syrup or powder created by drawing off and dehydrating the liquid sugar solution from malted barley.

Original Gravity (OG)

The specific gravity of wort before fermentation begins to convert the fermentable sugars.


The act of adding yeast to cooled wort in order to commence fermentation

Rack (or Racking)

The process of carefully transferring beer from one container to another. Normally this is used in relation to the transfer between a primary and secondary fermentation vessel to move the beer off the solid matter (trub) that settles during fermentation.


Rinsing the spent grain with hot water to extract as much of the fermentable sugar from the grain as possible.

Specific Gravity (SG)

The density of a solution as compared to water. This is measured in grams per millilitre so that 1ml of water weighs 1gram or 1.000


Soaking malted grain in hot water to extract the fermentable sugars from the grain and dissolve them in the wort.

Trub (pronounced troob)

The layer of sediment at the bottom of the fermenter made up of the proteins, hops and dead yeast after the fermentation process.


The sweet solution made up of water, malt, hops and other fermentable sugars before yeast is added to ferment it into beer.