Boueberry S.G. dropping slowly, stuck fermentation?

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v8rx7guy

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Blueberry S.G. dropping slowly, stuck fermentation?

I am making a 6 gallon batch of blueberry wine. I started the fermentation 7 days ago at 1.090 specific gravity. I am using redstar pasteur red yeast and added nutrient at the start and about 1/2 sugar depletion (missed the 1/3 mark by a half a day). THe spedific gravity dropped down to 1.050 fairly quickly, but now it has taken 3 days to drop to 1.040. I read a lot bout stuck fermentation, but I am not sure if that is what I am experiencing... I am clearly still making CO2 as the cap forms quickly throughut the day after punch down. Fermentation temps have been between 70 and 72.

Is this normal for the fermentation to slow down so drastically? If not, what should I do? Also, how much longer should I keep the juice in contact with the berry skins... all the way down to 1.010 like the wine I make?
 

Johnd

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I am making a 6 gallon batch of blueberry wine. I started the fermentation 7 days ago at 1.090 specific gravity. I am using redstar pasteur red yeast and added nutrient at the start and about 1/2 sugar depletion (missed the 1/3 mark by a half a day). THe spedific gravity dropped down to 1.050 fairly quickly, but now it has taken 3 days to drop to 1.040. I read a lot bout stuck fermentation, but I am not sure if that is what I am experiencing... I am clearly still making CO2 as the cap forms quickly throughut the day after punch down. Fermentation temps have been between 70 and 72.

Is this normal for the fermentation to slow down so drastically? If not, what should I do? Also, how much longer should I keep the juice in contact with the berry skins... all the way down to 1.010 like the wine I make?
What is the pH of your must? Blueberry is typically very acidic, as the alcohol content increases, that in combination with low pH can challenge your yeast a bit. It would help if you could get your temps up into the mid 70's as well.

I typically press and rack to glass in similar timing as grape wine, somewhere around 1.000.
 

v8rx7guy

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What is the pH of your must? Blueberry is typically very acidic, as the alcohol content increases, that in combination with low pH can challenge your yeast a bit. It would help if you could get your temps up into the mid 70's as well.

I typically press and rack to glass in similar timing as grape wine, somewhere around 1.000.
Yeah... pH was 2.90 when starting the fermentation. It didnt concern me so much because the fermentation started so quickly and was so strong out of the gates. Now that its slowed down so much it does have me a bit concerned. I will bump up the temps a bit. Otherwise, raise the pH with a proper dose en of potassium bicarbonate?
 

Johnd

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Yeah... pH was 2.90 when starting the fermentation. It didnt concern me so much because the fermentation started so quickly and was so strong out of the gates. Now that its slowed down so much it does have me a bit concerned. I will bump up the temps a bit. Otherwise, raise the pH with a proper dose en of potassium bicarbonate?
Yes, always better when it's under 3 to give it a little preferm bump up.
 

AKsarben

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We have always had difficulty fermenting Blueberry at our winery. We never ferment it on the skins. We crush back into bin boxes and let it soak for 24 hours, then press. Plenty enough color and flavor. We have won several awards with it. On the skins gives it a strange flavor.

I use the strongest yeast I have, Uvaferm 43 for fermentation, and superfood, and sometimes 1.5 lbs of DAP as well. They spray blueberries around her pretty heavily with fungicides and I suspect that since yeast is a fungus, that there is some residual influence on the fermentation. Usually takes a good month to 6 weeks to ferment blueberry.
 

Stressbaby

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We have always had difficulty fermenting Blueberry at our winery. We never ferment it on the skins. We crush back into bin boxes and let it soak for 24 hours, then press. Plenty enough color and flavor. We have won several awards with it. On the skins gives it a strange flavor.

I use the strongest yeast I have, Uvaferm 43 for fermentation, and superfood, and sometimes 1.5 lbs of DAP as well. They spray blueberries around her pretty heavily with fungicides and I suspect that since yeast is a fungus, that there is some residual influence on the fermentation. Usually takes a good month to 6 weeks to ferment blueberry.
This is interesting, thanks for posting. So am I correct, you
basically cold macerate the blueberries for 24 hours?

I went back and looked at my notes from this year, and lo and behold, my blueberry wine got stuck as well with Montrachet. I had to finish with K1-V1116.
 

AKsarben

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Yes, that is correct. We crush back into bin boxes adding Scott Labs Color Pro enzyme and then press. They give it around 100 ppm SO2 during the picking directly into the bin boxes we send before we receive them. I'll have to look tomorrow to see how many tons we received this year of blueberries.


K1 yeast is a killer yeast and once in a winery it is hard to eradicate. We use U-43 for the strongest yeast we have for fermentations. Works pretty nice.
 

Stressbaby

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Yes, that is correct. We crush back into bin boxes adding Scott Labs Color Pro enzyme and then press. They give it around 100 ppm SO2 during the picking directly into the bin boxes we send before we receive them. I'll have to look tomorrow to see how many tons we received this year of blueberries.


K1 yeast is a killer yeast and once in a winery it is hard to eradicate. We use U-43 for the strongest yeast we have for fermentations. Works pretty nice.
Thanks, one more question. You mentioned a "strange taste" you got when blueberry is fermented on the skins. Can you describe that? This is the first I've heard of any concerns fermenting blueberry on the skins.
 

AKsarben

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This year, 2016, we have crushed 36.805 Tons or in pounds, 73,610 lbs of blueberries. :)
 

v8rx7guy

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Good news is that I am down to 1.018 now. I have a batch thread going in "country winemaking" that describes some of the things I did. I am hoping to press this weekend!
 
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