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Alcohol levels in wine are increasingly becoming a hot topic in the wine world. Here in the US there is significant use of reverse osmosis (RO) to reduce alcohol levels in wine. However wineries/winemakers are not keen to come out of the closet about their use of the technology. This makes it difficult to find wines that have undergone RO in order to identify any changes that the process may make to a wine beyond removal of alcohol (and apaprently volatile acidity (VA)).
I was therefore quite pleased to find this post on the West Coast Wine Net forum. The 3 year old post provides tasting notes on a Syrah (made by students at Fresno State University in California) that was made with differing levels of alcohol.
Fruit for the experiment was harvested at 31 Brix (the 0.55 multiplier doesn't account for the 18% alcohol) with a 2-day cold-soak, the fermentation ran for 17 days at 55-60 degreesF. Pressed at 1 Brix, the fermentation proceeded to 0.6% rs afore sticking.
..........the wine was sent to Vinovation for reverse osmosis to reduce the alcohol, from the original 18.0% to 12.8%,and everything in between in 0.1% increments. The four "sweet spots" at above alcohols were selected for aging 6 months in American oak. Each lot completed alcoholic fermentation except the original 18.0%, stopping at <0.2%>. Three of the four reduced alcohol lots finished M-L fermentation. Then given a 5 micron filteration and packaged in a slick redwood box.
The final wines were 13.35%, 13.75%, 14.35%, 15.0%, and 18.0% alcohol. And after the tasting the 17 participants rated the 13.35% the worst wine (14 votes) and the 15% the best (8 votes) followed by the 14.35% with 5 votes. One individual favored the 18% wine!
The comments on the tasting, from several individuals, are interesting and worth reading.
One point to note is a comment by Mike Officer (of Carlisle Winery & Vineyards) that it's virtually impossible to get syrah to taste pruney or raisiny. Our syrah last year was around 31 brix as well. Not a trace of overripe character. I'm not sure why syrah behaves like this but might have something to do with phloems cavitating around 22 brix. It's definitely a physiological issue unique to syrah.
I must admit that I don't recall finding overt prune character in Syrah/Shiraz except for the 2004 Massena The Eleventh Hour Shiraz (Barossa Valley).
Any more examples of approaches that have tested whether or not alcohol levels adversely affect wine appreciation?