Cooking your grapes first

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Jan 17, 2017
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Just curious if anyone has ever done this or if anyone has any feedback as to what the impact is from doing this. We do this every year w/ a crate of Alicante that we add to our zinfandel must. De-stem everything by hand, then put it in a big pot on the stove just until the skins are about to break. Let it cool overnight, then add it to the must, which is usually 20crates of Zin. The color and aroma from the Alicante is amazing, but I'm just curious if anyone has a professional opinion on this since its really just a family tradition. Separately, we'll make a "Vino Cotto", which is an old school Italian homemade wine that tastes similar to a port. Tried searching "cotto" on the forum- but most of what I came across was tied to food recipes.


Veteran Winemaker
Jun 16, 2014
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You're not really doing anything terribly unusual. The commercial wine industry has been do this in one form or another for many years, it's called thermovinification; technology has changed the methods of heating and cooling quite a bit over the years. The heating of the grape must causes a rapid release of color and tannins etc.
I do something similar when making a yeast starter; I typically heat 3 gallons of grape must to 160F with constant stirring, hold for 15min, and then cool, make any necessary adjustments, and then pitch re-hydrated yeast. I have always noticed rich color and aroma immediately after the treatment. I have often thought of running a 5gal experiment to see how the treated wine would differ from the untreated, just never got around to it.
My in-laws always made vino cotto during wine season, they used it for some type of Italian cookies that were made around Christmas time.


Aug 13, 2009
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I've personally never heard of anyone heating grapes, but I guess there would be nothing wrong with doing so.

You're obviously pasturizing it.

Traditionally people aim for a cold soak then add the yeast and punch down the cap down for a few days.

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