Thermovinification/Maceration?

Lately I've been running across quite a few descriptors---many of them in the Bordeaux Rouge, but that may not be the only area we're dealing with---where the techniques of 'thermovinification and maceration' are mentioned as primary techniques.

Anyone actually up to date on those (versus the usual winegeek eveyone-has-an-opinion, I mean)?

I'm assuming (and I know how perilous that can be!) that the thermovinification/maceration is an attempt to get maximum maceration in a much shorter time period, as opposed to the slower, cold maceration technique.

But I'm also wondering what effect that would have on what is being pulled from the thermo-maceration---as in, mostly, the pyrazine elements (herbaceous, peppery or vegetal) and other stuff? Also how controversial and how widely used is this process nowadays?

Thanks in advance for any reply.

Also referred to as "Hot Press". Here's a link: http://www.homewinemakingjuices.com/manual.html

Hi Hoke,
This is from “Wine Science: Principles, Practice, Perception” by Ron S Jackson;
http://books.google.com/books?id=9En27z ... es&f=false


There are all sorts of ways one can perform thermo vinification. As Howie noted the must (crushed mixture) could be heated, held at a certain temperature for a given amount of time and then cooled to favorable fermentation temperatures (or in the case of preparing juice or concentrate pressed and separated from the skins- “hot press”).
David Bird describes another method to perform thermo-vinification. The grapes are de-stemmed, and then the uncrushed (whole) berries are passed rapidly through a heat exchanger, which heats only the “outer” surface layer of the berries. Hopefully weakening the skin cells (and allowing the skin of the berries to release their “goodness”) while the juice itself remains fairly “cold”.

Besides giving a wine more color, they say it might reduce vegetal aromas and might actually enhance fruity aromas and flavors (that’s if it is done right and you don’t “cook” the berries or the precious juice). They also think it may destroy the polyphenoloxidase enzyme that could cause premature oxidation, thus requiring a lower dose of sulfur dioxide.

Salute

Thanks, guys.

the "thermal vinification" used by Beaucastel, described by Francois Perrin (if memory serves correctly) is about eliminating polyphenyloxidase, to prevent the oxidation to which Grenache is so susceptible.

And they've been doing that for a long time, Steve---I remember M. Perrin taking me through the winery in...oh, 1986, I think it was...and showing me the apparatus they'd had installed to do the thermo for the must. He said they did it back when his father was running the show, and had continued it ever since. At that time, though, it was considered an unusual procedure. Now, apparently, it has become fairly standard in Bordeaux, at least in the less expensive producers (I assume as an economical measure); wonder how many of the big chateau are using this process?

[James Roscoe]

Is Steve using the process? Is it considered manipulative? It sounds like good practice if a certain variety or vintage is subject to oxidation or other faults that can be prevented by this process.

the "thermal vinification" used by Beaucastel, described by Francois Perrin (if memory serves correctly) is about eliminating polyphenyloxidase, to prevent the oxidation to which Grenache is so susceptible.

That's what they tell us, at least. When we visited there and I saw how squeaky clean everything was kept (compared to other cellars we toured), I had to wonder whether they'd found that their perennial brett problem was because Brettanomyces is a wild yeast in their vineyards, and the steam-cleaning of the grapes is done to kill it off.

-Paul W.

the "thermal vinification" used by Beaucastel, described by Francois Perrin (if memory serves correctly) is about eliminating polyphenyloxidase, to prevent the oxidation to which Grenache is so susceptible.

That's what they tell us, at least. When we visited there and I saw how squeaky clean everything was kept (compared to other cellars we toured), I had to wonder whether they'd found that their perennial brett problem was because Brettanomyces is a wild yeast in their vineyards, and the steam-cleaning of the grapes is done to kill it off.

-Paul W.

If so, it apparently doesn't work very well.

I don’t know if I would compare “steam cleaning” or “steam sterilization” (where the object being cleaned or sterilized makes direct contact with the steam) as the same thing as passing through a heat exchanger (where only heat is exchanged).
Do you really think that by steam cleaning a barrel with a portable steam cleaning one can rid the barrel totally of a “Brett” infection? For the steam to be effective it would have to be at the appropriate temperature and duration (could the barrel itself withstand it) making direct contact with the microorganism itself.

Salute

BTW the site Hoke made reference to in his post “Rating Wine Controversy: It’s ba-a-a-a-a-ck!” “The Palate Press has a nice article on Brett.

http://palatepress.com/2010/10/meet-bre ... your-wine/

Salute