The starting point for making red wines, as with white wines,
comes with crushing and destemming the red or black-skinned
grapes. Occasionally the winemaker may decide not to destem, as
the stems will add further flavour compounds and tannins to the
grape must. The crushed grapes are then moved into the
fermentation vessel. Stainless steel tanks are the most common
vessel for the fermentation of red wines, as they allow easy
access to the liquid for mixing the grape skins with the liquid,
and also provide for temperature control. The addition of yeast
starts the fermentation, and sulphur dioxide helps to prevent
oxidation. The carbon dioxide produced by the fermentation
process means that all of the solid material soon rises to the
surface of the fermentation vessel. These solids need to be
mixed thoroughly with the liquid in order to extract the colour,
phenolics, flavour compounds and tannins which are vitally
important to red wines. To do this, the winemaker can either
punch down the cap of solids using ro