Appears in
Oxford Companion to Wine

By Jancis Robinson

Published 2006

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respiration, biochemical process in animals and plants, including vines, which provides the chemical energy required for other reactions and for growth. Respiration may be considered the opposite of photosynthesis in that oxygen is consumed and carbon dioxide and energy released, according to the following formula:

In addition to sugars, other compounds such as starch, fats, amino acids, organic acids, and other substances may be broken down to release energy.

In plants, temperature has a major effect on respiration rate. The rate of respiration approximately doubles for each 10 °C/18 °F increase in temperature. Of particular interest to wine drinkers is the respiration of malic acid, which takes place in the grape during ripening. This reaction depends on temperature, an important reason why acidity levels are higher in wines from cooler climates.