Winemaking
Ice wine
Pressing grapes while frozen, so the ice stays behind and only concentrated juice comes out.
Overview
Grapes are left on the vine into winter and picked frozen, usually at around −7°C or colder.
Water freezes; sugar does not. Pressing the frozen fruit yields a small quantity of intensely concentrated juice and leaves the ice in the press.
It depends entirely on a hard frost arriving before the crop rots or is eaten. Warming winters have made it markedly less reliable in Germany, and some recent years have produced none.
Sources
Sources consulted
More in winemaking
Winemaking
Fermentation
Yeast converting sugar into alcohol and carbon dioxide — the step that makes wine wine.
Winemaking
How red wine is made
Fermenting grape juice in contact with the skins, which is where colour and tannin come from.
Winemaking
How white wine is made
Pressing the juice off the skins before fermentation, then fermenting the clear juice.