Comments on: Restarting a stuck fermentation http://www.washingtonwinemaker.com/blog/2007/09/11/restarting-a-stuck-fermentation/ Growing grapes and making wine in Bellevue Thu, 28 Aug 2008 10:10:32 +0000 http://wordpress.org/?v=2.3 By: Erroll http://www.washingtonwinemaker.com/blog/2007/09/11/restarting-a-stuck-fermentation/#comment-1143 Erroll Tue, 18 Sep 2007 23:57:30 +0000 http://www.washingtonwinemaker.com/blog/2007/09/11/restarting-a-stuck-fermentation/#comment-1143 Hello Earl, Two things come to mind. The first is that if you rack before your must has fermented out, you can sometimes leave too much yeast behind and the clear wine that you rack wont have enough yeast in it to continue fermenting. Your comment that "the lively musts contained the most pulp" made me wonder about this. If that's what happened here, then you should make a starter. Once the starter is going, add must to it, doubling the volume every four hours. The second thing is the acid. I'm confused when you say that the acid measured 1.5, but you're "not sure what this refers to." I just can't believe that you have a pH of 1.5, so I'm going to assume that you mean a titratable acidity (TA) of 1.5% (15 g/L) as tartaric - is this right? That is high, but when trying to determine if a must is too acidic for the yeast, pH is a much more important measurement than TA. You should measure the pH. If it is less than 3, then you should try to neutralize some of the acid, <a href="http://www.washingtonwinemaker.com/blog/2007/07/25/oregano-wine-recipe-restarting-a-stuck-fermentation/" rel="nofollow">as I did</a> to get my Oregano wine going again. Do some trials on a sample of your must until you get the pH between 3 and 4. Then scale up the amount of neutralizing agent that you used to treat an entire carboy. For example, if you need 1.5 grams of potassium bicarbonate (KHCO3) to restore the pH of a 1 liter sample, then you would add 28.5 grams of KHCO3 (about 5 tsp) to a 19 liter (5 gallon) carboy. Good luck, and let me know how it turns out. Erroll Hello Earl,

Two things come to mind. The first is that if you rack before your must has fermented out, you can sometimes leave too much yeast behind and the clear wine that you rack wont have enough yeast in it to continue fermenting. Your comment that “the lively musts contained the most pulp” made me wonder about this. If that’s what happened here, then you should make a starter. Once the starter is going, add must to it, doubling the volume every four hours.

The second thing is the acid. I’m confused when you say that the acid measured 1.5, but you’re “not sure what this refers to.” I just can’t believe that you have a pH of 1.5, so I’m going to assume that you mean a titratable acidity (TA) of 1.5% (15 g/L) as tartaric - is this right?

That is high, but when trying to determine if a must is too acidic for the yeast, pH is a much more important measurement than TA. You should measure the pH. If it is less than 3, then you should try to neutralize some of the acid, as I did to get my Oregano wine going again. Do some trials on a sample of your must until you get the pH between 3 and 4. Then scale up the amount of neutralizing agent that you used to treat an entire carboy. For example, if you need 1.5 grams of potassium bicarbonate (KHCO3) to restore the pH of a 1 liter sample, then you would add 28.5 grams of KHCO3 (about 5 tsp) to a 19 liter (5 gallon) carboy.

Good luck, and let me know how it turns out.

Erroll

]]> By: earl krans http://www.washingtonwinemaker.com/blog/2007/09/11/restarting-a-stuck-fermentation/#comment-1139 earl krans Tue, 18 Sep 2007 19:44:43 +0000 http://www.washingtonwinemaker.com/blog/2007/09/11/restarting-a-stuck-fermentation/#comment-1139 Stuck Must of plumb; I have been fighting a stuck must of 22 gallons of plumb wine for 6 days. This Must was taken off the skins and pulp after 7 days where it was working fine, and had dropped SG from 1.095 to 1.27. Upon putting in 6 gal. glass, two carboys were dead, and the 3rd active. Same of 5 one gallon. 3 were dead. The lively musts contained the most pulp sediment. The must is very acid and measured 1.5. I'm more used to ph, so i'm not sure what this refers to, but it's much more acid than needed for the yeast. Can my must be so acid that yeast is retarded? I have added more yeast culture V1116, with no results. Same with yeast Nutrient. I am now experimenting with 3 different yeasts, sugar adds, and carbonate acid neutralizer, in different concentrations with grape juice and/or water. Any comments on what might be going on? regards, Earl in coos bay oregon Stuck Must of plumb;

I have been fighting a stuck must of 22 gallons of plumb wine for 6 days. This Must was taken off the skins and pulp after 7 days where it was working fine, and had dropped SG from 1.095 to 1.27.

Upon putting in 6 gal. glass, two carboys were dead, and the 3rd active. Same of 5 one gallon. 3 were dead. The lively musts contained the most pulp sediment.

The must is very acid and measured 1.5. I’m more used to ph, so i’m not sure what this refers to, but it’s much more acid than needed for the yeast. Can my must be so acid that yeast is retarded?

I have added more yeast culture V1116, with no results. Same with yeast Nutrient. I am now experimenting with 3 different yeasts, sugar adds, and carbonate acid neutralizer, in different concentrations with grape juice and/or water.

Any comments on what might be going on?

regards, Earl in coos bay oregon

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