My oregano wine has been fermenting very slowly, and I suspected a pH problem. I was following a recipe that called for 3 tsp of acid blend. I decided to add only 1 tsp at the beginning, because I was afraid the pH could drop so low that it would inhibit the yeast. The must was mainly sugar and water, so there wasn’t much to buffer it – a little acid could push the pH a long way. Yeast has a difficult time when the pH drops below 3. I decided to take a sample and do some measurements. The pH meter, reading 2.69, confirmed my suspicion. The specific gravity was 1.052, which is less than the 1.060 on 6/30/07. That means it’s still fermenting, but it’s been over a month and it’s still got a long way to go. I measured the TA as 6 g/L (tartaric). I’m not sure what to do about this yet. I might be able to rack it and let it ferment out slowly under an airlock. I could try and neutralize some of the acid, pushing up the pH, to get fermentation going again.
Update 7/25/2007 – Fixing the pH crash by neutralizing acid
To fix the pH crash, I neutralized some of the acid with potassium bicarbonate (KHCO3). This will raise the pH and should get things going again
Pingback: Washington Winemaker » Blog Archive » Oregano Wine Recipe: restarting a stuck fermentation