| Term | Definition |
|---|---|
| Decoction | Exhaustive system of mashing in which portions of the wort are removed, heated, then returned to the original vessel. It does not occur without the presence of water.
|
| Dextrin | A soluble, gummy unfermentable carbohydrate formed by the decomposition of starch by heat, acids or enzymes in barley. It gives the beer flavor, body, and mouthfeel. Lower temperatures produce more dextrin and less sugar. While higher temperatures produce more sugars and less dextrin.
|
| Diacetyl | A volatile compound in beer that contributes to a butterscotch flavor, measured in parts per million.
|
| Diastase | An enzyme mixture capable of gelatinizing and converting starch to dextrins and sugars.
|
| Diffusion | The flow of molecules, usually, but not necessarily, through a membrane.
|
| Dimethyl sulfide (DMS) | A sulfur compound offing, giving the taste and aroma of sweet corn as a result of the short or weak boil of the wort, slow wort chilling, or bacterial infection.
|
| Disaccharide | The sugar resulting from the condensation of two molecules of a monosaccharide, with the loss of water. Examples: sucrose, maltose, and lactose.
|
| Dispersion | Any mixture where one substance is very intimately intermingled with another. Most frequently a dispersion refers to a colloidal suspension.
|
| Dissociation | The splitting of a compound into two or more simpler molecules, atoms, or ions.
|
| Distillation | The process of heating a liquid to its boiling point, removing the vapors through a cooling and condensing apparatus, and finally collecting the condensed vapors, as a liquid, in a separate receiver. Method of separating liquids from solids or liquids having different boiling points from each other by evaporation and condensation of the more volatile component.
|
| Dosage | The addition of yeast and/or sugar to the cask or bottle to aid secondary fermentation.
|
| Doubling | The addition of unyeasted wort to beer in the first stage of the main fermentation.
|
| Draft (Draught) | The process of dispensing beer from a bright tank, cask or, keg, by hand pump, pressure from an air pump or, injected carbon dioxide inserted into the beer container prior to sealing.
|
| Dry-hopping | The addition of dry hops to fermenting or aging beer to increase its hop character or aroma.
|