Beer Brewing

Glossary

D

DECARBONATE - To remove carbonate and bicarbonate ions from water, either by boiling or by adding chemicals.

DECOCTION MASHING - Mashing is carried out in a series of controlled temperature stages by removing a portion of the grist from the mash and boiled in the mash kettle and latter returned to the mash tun thus gradually raising the temperature of the entire mash. The process usually is repeated two or three times with each successive step, or decoction, used to raise the temperature of the main mash. Decoction mashing typically achieves a high rate of extraction and increased amount of malt character.

DEFLOCULATION - The action of breaking up solid chunks into smaller particles by chemical action and mechanical action.

DEIONIZED WATER - Water that has had ions removed by an ion-exchanger.

DENSITY - The measurement of the weight of a solution, as compared with the weight of an equal volume of water. Density can either be expressed as degrees Plato or as specific gravity. Degrees Plato is most commonly used by professional brewers in the United States and Continental Europe whereas specific gravity is more than likely to be used by homebrewers.

DETERGENT - A cleaning agent, compounded from chemicals that acts as a wetting agent and emulsifier.

DEXTRINS - A complex, unfermentable and tasteless carbohydrates that contribute to the final gravity and body of beer; some dextrins remain undissolved in the finished beer giving it a malty sweetness. In recent years have been referred to alpha-glucans.

DEXTRINIZATION - The enzymatic process by which alpha amylase degrades soluble starch molecules into dextrin molecules.

DEXTROSE - A common monosaccharide, the building block for dextrins, starches, and other sugars.

DIACETYL - A volatile compound produced in beer by the oxidative decarboxyla­tion of acetohydroxyl acids produced by yeasts. Diacetyl is an important to beer flavor and aroma producing a butterscotch flavor to beer. It is arguably a desired flavor note in English ales but a major flaw if detected in lagers and lighter beers.

DIASTASE - An enzyme capable of changing starches into maltose and later into dextrose.

DIASTATIC POWER - Diastatic power is a measure of the total amylase content of a given sample of malt; usually expressed in degrees Lintner.

DIKETONE - Aromatic, volatile, compound perceivable in minute concentration, from yeast or Pediococcus metabo­lism.

DIMETHYL SULFIDE (DMS) - A major sulfur compound of lagers not found in British ales because their malts are highly modified at very high temperatures. DMS is released during boiling as a gas that dissipates into the atmosphere. The precursor of DMS, S-methylmethionine, remains present in the wort and converts to DMS if the wort is not cooled rapidly enough or if it is allowed to sit after cooling.

DIMPLE JACKETS - A type of heat transfer surface custom designed to produce maximum efficiency and uniformity through single- or multi-zone controlled flow of heating or cooling media. Available in ammonia-Freon (AF) or water-glycol (WG) styles.

DISACCHARIDES - Sugar group; two monosaccharide molecules joined by the removal of a water molecule. Common disaccharides are sucrose, maltose, and lactose.

DISINFECTANT - A chemical agent that is capable of inhibiting growth of microorganisms or otherwise eliminating them from an area or surface.

DISPERSION - The breaking up soil clumps into smaller particles, which are less likely to redeposit on the surface.

DOSAGE - The addition of yeast and/or sugar to the cask or bottle to assist in secondary fermentation.

DOUGHING-IN - The gradual addition of water to crushed malt to prevent the formation of dry spots in the mash. Also is referred to as mashing-in.

DRAFT BEER - Beer drawn from casks or kegs rather than canned or bottled. It is often referred to as a draught beer.

DRY HOPPING - The addition of loose dry hops during wort boiling or conditioning to increase the aroma and hop character of the finished beer without affecting its bitterness. In Britain, dry hopping more specifically refers to the addition of fresh hops to a cask of draft beer when it racked from the primary fermenter.

DRY MALT - Dry malt is malt extract in dry, powdered form as opposed to liquid or syrup malt.