The short phase between harvesting, pressing and fermentation plays an important role in winemaking. The period should be as short as possible and the grapes should be moved or stressed mechanically as little as possible in order to avoid undesirable oxygen contact and loss of flavour. The composition of the grape must (ingredients) determines the necessary treatment. Care must be taken to ensure that no undesirable microorganisms such as acetobacter (acetic acid bacteria) get into the must. Sulphurisation of the mash/grapes is obligatory.
The grape must should only be sulphurised if it has been left to stand for a long time or if the grapes are rotten. A aerate promotes the formation of yeasts and thus fermentation. However, this is only recommended for over-sulphurised must, heavily rotten grapes or white pressing of dark grapes. A special process is must oxidation with a deliberate massive supply of oxygen. Degumming (must clarification), on the other hand, is obligatory in order to remove undesirable substances and thus prevent fermentation faults and the resulting premature ageing of the wine.
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Egon Mark
Diplom-Sommelier, Weinakademiker und Weinberater, Volders (Österreich)