After the grapes have been crushed nothing is thrown away. The stalks are used in animal husbandry (pigs are particularly fond of them) and the skins go for distillation.
Vaporisation and condensation of the 'waste' from the pressed grapes produce the Italian drink 'grappa' and the French 'marc'. Grappa is actually the liquid which is formed from the vapours of the skins (which are boiled) and is then condensed.
Only the 'heart' of these vapours ends up as grappa. During distillation the first vapours are discarded (the 'head') as are the last ones (the 'tail'). Skins from a single grape variety may be used (single grape variety grappa) or those of several different grapes. Wine is also used to produce spirits: when the alcohol is extracted from wine by distilling different techniques enable cognac, armagnac, brandy and wine spirits in general to be obtained.