This chemical compound (also known as malic acid, hydroxy succinic acid or malic acid) is one of the three most important organic acids in wine alongside tartaric acid and citric acid. It is mainly found in unripe apples, barberries, quinces, gooseberries, rowanberries and grapes. It was given its name because it was first isolated from apple juice and described by the German pharmacist Carl Wilhelm Scheele (1742-1786) in 1785. Apple juice from special apple varieties is also used to produce cider, and French cider in particular has a long tradition.
It has a high content of up to 20 g/l in the unripe grapes and between 0.5 and 6 g/l in the wine. Parallel to the storage of sugar during berry ripening, the must acids are reduced. Malic acid is converted into sugar during cell metabolism at a temperature between 20 and 30 °C, while tartaric acid is only broken down at higher temperatures. This is why the remaining proportion of tartaric acid is always higher in ripe grapes. Tartaric acid is considered a soft, pleasant acidity, whereas malic acid is a more aggressive-tasting acidity, which makes the wine taste angular (hard).
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