Comments on: About

By: Daniel

Daniel — Tue, 31 Aug 2010 05:56:41 +0000

Thank you for your kind words. Based on the fact that you have fermented “good” grapes successfully without any problems, we can conclude that spoilage yeasts kicked in and started fermentation when grapes started splitting with heavy rain.

By: Frank

Frank — Mon, 30 Aug 2010 23:23:28 +0000

Thanks for the r esponse. Live and learn I guess. I had picked some of the same grapes before the rain and they fermented just fine. I’m glad I’m not making wine for a living, it is a challenge. I’ll do some testing and use some of your ideas as I progress as you suggested. I have to say that your book is the most thorough I’ve read on wine making, especially for the home wine making and novice like me. I recommend it to all my wine-making friends.

By: Daniel

Daniel — Mon, 30 Aug 2010 12:20:26 +0000

Um! Doesn’t sound good. I’m assuming that it is in fact ethyl acetate that you are smelling. It sounds like you have some indigenous yeasts that kicked in and converted the acetate into its ester, ethyl acetate, during fermentation. Fermentation probably started when split grapes were still hanging. A higher dosage of SO2 was required at crush. Quite possibly, even the 71B might have generated some under the stressful conditions, esp. if it was deprived of nutrients (what you added might have been too late). A hot fermentation may have been a contributing factor too. Then there is the slight chance of a premature MLF, but that’s probably not the case since you have added 40 ppm of sulfite — do a MLF test and check anyways. MLF produces some ethyl acetate but it’s usually small, unless you have some other bacteria or the MLF happened under stressful conditions. At this point, there’s not much you can do to reduce the ethyl acetate. Measure the pH and add a good dose of SO2. Keep your SO2 up all along. I would avoid an MLF. If you need to reduce the malic acid, I would consider double-salt precipitation. In the end, you’ll have a subpar wine, and what you do all depends on how bad the ethyl acetate is. You can blend in another wine if it’s not too bad, but I’m afraid the wine is destined for the sewer. Sorry. I wish I had better news.

By: Frank

Frank — Sun, 29 Aug 2010 20:09:46 +0000

I don’t find anything in your book about off odors during fermentation. We harvested 1200 lbs of St. Croix under not very good conditions – we had three inches of rain right before harvest which caused some skin spliting. The yellow jackets were all over the place (and I assume fruit flies although we didn’t acutally see those in abundance). Crushed and added 40ppm SO2 but didn’t want to add more because we plan on a MLF. We innoculated with 71B yeast 18 hours after crush. We added Fermaid K (15 g/hL) when the Brix dropped 10% and plan on another 10g/hL soon. The fermentation has an odor of ethyl acetate (nail polish remover). I assume this is caused by acetic acid bacteria or starving yeasts. Any suggestion in addition to what I am already doing.

By: Frank

Frank — Tue, 24 Aug 2010 20:57:28 +0000

Thanks for the timely response. I will refer to your book and look forward to the next issue of Winemaker.