a b c d e f g h i l m n o p r s t v w y

acetaldehyde An oxidation product of ethyl alcohol (q.v.). A fault when sensed in table wines and beers, but acceptable as an ingredient in the bouquet of sherry or Madeira. It may be recognised by its sharp, penetrating odour.
acetic Term used to describe an acetified wine or beer, recognised by a sharp, vinegary smell and taste.
acetification A serious disorder in wine or beer, caused by acetic acid bacteria producing a sour, acrid taint of acetic acid, ethyl acetate and amyl acetate. Exclusion of air is the best prevention.
acid A sour-tasting substance, e.g. citric acid as found in lemon juice. The principal acids found in wine are tartaric, malic and citric, but there are important small quantities of many others. The word is also used to describe an excess of acidity in wine or beer, as in "an acid wine".
acidity The acid taste. The acidity tasted in a wine or beer is influenced by many constituents of the liquid which can mask or suppress the acid taste. Also the measure of the acid content of a wine, usually expressed in parts per thousand (ppt), or as a percentage, either as tartaric or sulphuric acid.
adjunct An ingredient for brewing, other than malted barley, used to give colour, flavour, additional extract, or to reduce the chance of protein haze.
aerobic fermentation Fermentation in the presence of air. Essential in the initial stages of fermentation in order to promote yeast growth, but must be limited in order to allow efficient production of alcohol and to prevent spoilage.
after-taste The total sensation - odour, taste and "mouth-feel" - remaining in the mouth, throat and back of the nose after a wine or beer has been swallowed. Also known as the farewell.
alcohol One of a large group of organic compounds, each containing the same specific chemical (hydroxyl) group. The principal alcohol present in wines and beers is ethyl alcohol (q.v.) but there are others in small quantities which contribute to flavour and bouquet.
amber Coloured like the substance amber, i.e. deep yellow to mid-brown.
amino acids Compounds which are linked together to form proteins and which are probably important in the flavour and bouquet of wines and beers. Present in fruits, vegetables and cereals, they are also released during the degradation of proteins during the mashing of malt.
amyl acetate An ester formed from amyl alcohol and acetic acid having the odour known as "pear drops". It is normally present in very small quantities in wines and beers. An indication of acetification (q.v.) when present to any considerable extent.
anaerobic fermentation Fermentation in the absence of free oxygen, by the exclusion of air. The enzymes from yeast carry out a series of reactions, changing simple sugars such as glucose and fructose into ethyl alcohol and carbon dioxide.
apple flavour A taint in beers made from worts deficient in nutrients and which is exaggerated by fermentation at too high a temperature.
aroma Normally that part of the odour of a wine or beer that originates with the starting ingredients, but often synonymous with bouquet.
aromatic Describes a fragrant or spicy bouquet or flavour.
ascorbic acid Vitamin C. Present in fruits, vegetables and honey. Sometimes used as an antioxidant in wine but, unlike sulphur dioxide, does not prevent bacterial spoilage.
astringency The tactile sensation (dryness, puckering) in the mouth, caused by tannins and related substances. Not to be confused with bitterness.
attenuation The degree to which a beer has fermented, e.g. highly attenuated beers have low final gravities.
autolysis In a wine or beer, the breakdown of yeast cells. The decomposition products may affect the flavour. See "yeasty".

Last updated: 03/12/09
Copyright: 2006 NGWBJ