Wine Words Demystified: Destemmer

You know the deal; the more some folks learn about a topic, the more shortcuts/slang/acronyms/initials/technical jargon can be tossed around.  I’m here to help you understand those sometimes mysterious words and phrases, thus - Wine Words Demystified!  Since harvest is in full effect here in Northern California, I’ll be featuring harvest related terms the next several weeks!

This week’s word is Destemmer..

According to Karen MacNeil‘s The Wine Bible:

A machine that separates the stems from the grapes. When combined with a crusher, it is called a crusher-destemmer. juice that runs – freely – simply as the result of the weight  of the grapes, before any mechanical pressure is applied in a PRESS

Essentially, when grapes are placed in a destemmer, there are paddles that gently beat the grape making it jump off the stem. The stems are ejected from the machine. The used stems may be used for fertilizer in high pH soils.

With crusher-destemmer, the grapes are then dropped into a vessel where the crusher gently breaks the berry, but not the seed.

Here’s a cool video that shows a small scale crusher-destemmer in action:

A machine like the one above will set you back about $1,500.  A manual crusher-destemmer that operates via manual hand-cranking and can process up to 2,200 lbs of grapes an hour would set you back around $600.
The proper destemming and crushing of grapes is crucial to the winemaking process If the grapes are over-crushed the wine could end up excessively laced with bitter tannins because it will included crushed seeds which are very bitter.  The other potential downside of destemming and crushing grapes for making white wine is that the grapes can be bruised and exposed to oxygen, making oxidation (not a good thing) a risk.
On the other hand, some winemakers utilize whole cluster fermentation, whereby the whole grape cluster is fermented intact.  Whole cluster fermentation affects both aromatics and flavors in wine.

 

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