De-stemming / Crush
On your Sonoma and Napa winery tours, you will
likely see a large machine that looks like it has a huge corkscrew in
it leading up to a conveyor. This is the De-stemmer/Crusher machine.
Once picked by vineyard workers and collected into bins, grape clusters
are transferred to the De-stemmer/Crusher. This machine will separate
and discard the stems (which contain bitter and unwanted flavors) and
then lightly crush the grapes into a pulpy mass of juice, skins and
seeds called “must.” Prior to fermentation, the skins and
seeds of the white wine grapes will be removed from the juice or “pressed”
by means of a large air bag press, which inflates inside a large steel
cylinder forcing out the juice.