Malic acid
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Malic acid is an organic compound with the molecular formula HO2CCH(OH)CH2CO2H. It is a dicarboxylic acid that is made by all living organisms, contributes to the sour taste of fruits, and is used as a food additive. Malic acid has two stereoisomeric forms, though only the L-isomer exists naturally. The salts and esters of malic acid are known as malates. The malate anion is a metabolic intermediate in the citric acid cycle.
DL-Malic acid
Ripeness in viticulture
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In viticulture, ripeness is the completion of the ripening process of wine grapes on the vine which signals the beginning of harvest. What exactly constitutes ripeness will vary depending on what style of wine is being produced and what the winemaker and viticulturist personally believe constitutes ripeness. Once the grapes are harvested, the physical and chemical components of the grape which will influence a wine's quality are essentially set so determining the optimal moment of ripeness for harvest may be considered the most crucial decision in winemaking.
Grapes ripening on the vine.
Pinot noir grapes in the early stages of veraison. As the grapes ripen, the concentration of phenolic compounds like anthocyanins replaces the green color of chlorophyll in the grape berries which makes them black instead.
Pinot noir grapes that are destined for sparkling wine will be considered ripe much earlier than Pinot noir destined for still red wine.
Vineyard management techniques such as canopy management can influence the ripening process of grapes by balancing the amount of foliage needed for photosynthesis versus excessive foliage that shades the grapes and competes for the grapevine's resources.