My apologies for the lack of entries. I've been a little preoccupied by the fact that my wife was recently diagnosed with non-hogdkins lymphoma. She has her own blog to keep everyone informed on how everything is going. If you would like more information on her diagnosis and how she's doing, please visit http://battlelymphoma.blogspot.com/.
Now, back to wine-related topics. In my last blog entry, I had previously written about a new wine testing center up at Appalachian State in Boone. I decided to have the Lodi Zinfandel and the NC Syrah tested, mainly to confirm alcohol levels and malic acid content. I got the results back a few days ago, and I was shocked at the Zinfandel numbers. The calculation I had been using to calculate alcohol level was to take the Brix and multiply it by 0.55. I measured the Brix level of the Zin to be 26o. So the calculation would have been 26 * 0.55 = 14.3%. I figured the maximum alcohol was that I would end up with was maybe 15%. The test results show an alcohol level of 17.12%! Yikes! The only thing I can think of is that when I tested the Brix, there was still a lot of sugar in the pulp that hadn't broken down yet.
The yeast I was using wasn't supposed to allow it go beyond 16% so I'm not certain as to why it was able to get that high. The one good thing is it doesn't taste like it has a high alcohol level. At this point I am trying to decide what to do about it. Should I add acidulated water? Blend it with another wine? Or just leave it the way it is? The problem with leaving it the way it is, is the fact that one bottle will put you under the table. The malic acid content was 218 mg/100mls (21.8 mg/Liter), so it appears to have either already undergone malolactic fermentation, or there wasn't much malic acid in the grapes.
The Syrah came in where I expected with an alcohol level of about 12%. The malic acid content of the Syrah was even lower than the Zinfandel, coming in around 77 mg/100mls (7.7 mg/Liter). Though the pH readings indicate I will need to add some tartaric acid again.
So, let me ask my fellow winemakers out there. What would you do with the Zinfandel, and why?
Robbie,
ReplyDeleteI was sorry to learn of Kelly's illness, but glad to know she's improving and her prognosis is so good. Please tell her my thoughts and prayers are with her for a full and fast recovery.
This may be too late because you've probably already sulfited your Zin, but I like to get malic acid in the 50-75 ppm range before I feel it's truly done. However, I'm sure it's complete enough not to ferment when bottled which would be the main concern.
Regarding ABV and acidity--I would try to blend rather than add water or tartaric acid, if possible. Also, cold stabilizing may bring down acidity to an acceptable level without having to add tartaric acid.
My 2 cents. Keep us posted.
Fred Stokes