In the crushing operation, the grapes are usually passed between two rollers that gently split the berries. This is in order to:

• Increase flavour and tannin (and in reds, colour) extraction, by increasing the level of association between the skin and the pulp
• Allow for drainage of the ‘free-run’ juice and speed up the pressing process
• Homogenise the vintage and aerate in order to ease the start of the alcoholic fermentation (reds only)

However, it is important that crushing is not too violent, or it may cause damage to the pips or stems (if the vintage is not de-stemmed).

Some de-stemmers combine de-stemming operations with crushing, using adjustable rollers after the destemming cylinder. Equally, the pumping of de-stemmed grapes to tanks or presses will invariably cause some degree of crushing. Traditionally, grapes were crushed with bare feet; good healthy exercise!

Note that crushing is not appropriate for vintages destined for carbonic maceration or sparkling wine.