Ale A beer fermented with ale yeast (sometimes referred to as top-fermenting yeast because of the significant amount of activity on the top of the brew). Ale is normally fermented at temperatures above 16C.

Adjunct Any fermentable sugar (cane sugar, dextrose, honey, etc.) added to the wort.

Attenuation How far the yeast ferments the brew to final gravity.

Brewmaster The person behind the beer.

Conditioning Following full carbonation during secondary fermentation the beer continues to condition in the bottle, improving aroma and flavour, clearing the beer and making the yeast sediment more compact.

Dry Hopping An addition of hops to the brew in the fermenting vessel, primarily imparting aroma to the finished beer. May be infused as a “hop tea” prior adding and may also be added very late into the serving vessel.

Dextrose The equivalent to Glucose, but with a mirror-image molecular structure. Dextrose for home brewing is the shortened name for Dextrose Monohydrate, as it normally carries a water molecule.

Esters Aromatic compounds formed from alcohols by yeast action. They typically smell fruity and are more common in ale rather than lager.

Ethanol The type of alcohol in beer formed by yeast fermenting the sugars.

Fermentation The action of yeast metabolising the sugars available in the wort, with the main bi-products being carbon dioxide and alcohol. Regardless of the yeast type (ale or lager), fermentation activity occurs throughout the brew.

Final Gravity The specific gravity of the brew once the yeast has finished fermenting all the available sugars. FG is achieved once the specific gravity is stable over a couple of days.

Finings Most commonly derived from gelatine, added around ¾ of the way through primary fermentation, to assist in clearing the brew. The addition of finings is an intrusive method which can increase the risk of spoilage. Delaying bottling for a couple of days after FG and extending the conditioning time will clear the brew just as effectively.

Flocculation Once fermentation activity slows, the yeast clumps together and settles out of solution.

Fusel Alcohol May be produced from very high temperature fermentation, fusels have sharp solvent-like aromas and flavours.

Glucose One of the most basic units of sugar, a single sugar molecule.

Head retention The beer’s ability to maintain foam.

Hops Used to season beer in a similar manner to herbs in cooking. Primarily used for bittering the brew but also may be added for the purposes of flavour and aroma (see Late Hopping).

Hydrometer A device (often made of glass) used to measure the specific gravity of a fluid normally by floating it in a sample tube and measuring where the fluid cuts across the scale.

International Bittering Unit (IBU) The unit of measure for the amount of bitterness in the brew.

Krausen (kroyzen) The foamy head formed on top of the brew in the early stages of fermentation.

Lactose A non-fermentable, yet not very sweet, sugar. Lactose (derived from milk) may be added to Stout, for example, to increase residual sweetness.

Lager A beer brewed from lager yeast (sometimes referred to as bottom-fermenting yeast because of the lack of activity on the top of the brew). Normally fermented below 16C then lagered (stored for an extended period) prior to carbonating and packaging.

Lag Phase The period of adaptation and rapid aerobic growth of yeast upon pitching. The lag time typically lasts from 2-12 hours and is a time where nothing much appears to be happening.

Late Hopping The addition of hops with, typically, 15mins or less of the boil remaining. Primarily for flavour and aroma with a small amount of bitterness (also see Dry Hopping).

Maltodextrin A complex sugar with very little sweetness. Yeast does not ferment it completely, leaving more body (carbohydrate) in the brew.

Pitching Term for adding the yeast to the brew. Sprinkle dry yeast and stir in liquid yeast.

Primary Fermentation The initial fermentation, normally evident by krausen (and a scum ring), sediment (at the bottom of the fermenting vessel) and Carbon Dioxide. Most of the total attenuation occurs during this phase.

Priming Adding a small amount of fermentable sugar prior to bottling to give the beer carbonation.

Racking Transferring the brew from one vessel to another, normally with the intent of removing it from the sediment and other solids.

Sanitise To reduce the amount of micro-organisms to a minimum, normally performed after cleaning the equipment, using a chemical sanitiser.

Secondary Fermentation Fermenting the brew in a secondary pressure vessel, normally bottle or keg, with the addition of some priming sugar. This process carbonates the brew, giving it fizz.