Whole-Bunch Fermentation

whole-bunch fermentation, ultra-traditional method of red wine fermentation in which grape berries are not subjected to destemming. This was the default position before the introduction of the crusher-destemmer. Aside from the influence of the stems themselves, the process generally involves an element of carbonic maceration at the start of the ferment. The possible disadvantages are that, unless the stems are very ripe, i.e. well lignified, and the must is handled very gently, the stems may impart harsh tannins to the wine. The technique also involves a greater total capacity of fermentation vessels, which are often open-topped to allow punching down of the cap. The practical advantages are that the stems can ease the drainage of the juice through the cap, aerate the ferment so that it is slightly cooler, and encourage healthy oxygenation by increasing the cap’s interface with the atmosphere during maceration. The level of potassium in the juice is also increased slightly, resulting in lower acidity in the wine.