Blueberry stuck and smelly

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Noren

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I started a blueberry wine on July 19 and have about 7-8 gallons (1 x 6 gallon carboy and 2 x 1 gallon glass jugs). (pH is about 3.2) I noticed that the sg has stuck at around 1.045 and doesn't show any signs of activity. I put it on a heating pad (pad on the counter and the carboy and jugs on top) and that brought the temp up to around 28 C (82 F). There was a persistent ring of foam on the top and slow bubbling but very slow progress on dropping the SG. Then I noticed a peculiar smell that I couldn't quite identify (I think my sense of smell is not what it used to be, but this was very noticable). Its gotten worse and now it smells like rotten eggs. The juice still tastes sweet and doesn't have an off taste, just a very bad off smell. I added some more yeast nutrient but it seemed to only give the foam a brownish color. Above the foam (on the top inside of the carboy) there was also a very light tint of green, as if it was algae, but I'm not sure about what it actually is or was. I also added another packet of yeast (EC 1118) but that hasn't helped either - no new bubbling activity. I tried degassing it several days in a row and have racked it to a new carboy and then also poured most of the liquid out into a primary bucket and splashed it around to try to get rid of the gas. Then I put it back into the carboy and added some Kmeta to counteract any effect of oxygen. Today I saw that there was no foam on top but it seemed like there was a long ring of the new yeast that had gathered just under the surface near the top, just clumped together, obviously not doing anything useful.

I talked with a local wine brewer and he mentioned that blueberries naturally produce their own potassium sorbate! I tried to find some more info about that and it seems that others have mentioned it also. (Last year I had a failed attempt at getting a blueberry wine to finish fermenting as well, so that's 2-0). Do any others on this forum have any experience like this and if so, is there any hope for my wine? I've read that potassium sorbate is a birth control for yeast, so it could be that there is just not enough active yeast in my wine. IF that's the case could a possible remedy be to hydrate a new batch of yeast outside the wine and let it multiply to a decent level and then add that mixture to the wine? If so, how long to wait until the yeast multiplies to a decent level that can ferment an entire carboy?

Any help is appreciated!
 

Johnd

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I’ve never heard of blueberries producing potassium sorbate, so I’ll just set that aside.
The smell you’re detecting is H2S, produced by yeast when stressed for some reason. It can be very bad for wine if you don’t get it healthy and fermenting again. If you get rolling, it may just blow it out with no ill effect. If it gets out of control, but you’re able to get dry, it can be treated with Reduless.
Blueberries can be are very acidic, low in nutrients, and can give yeast fits. I always try to use a yeast with low pH tolerance, raise the pH to 3.35 or higher, use plenty of nutrients, and keep the temps above 75°F. Try getting all of those things in line.
You didn’t mention what your starting SG was, so I’m asking just to rule out the yeast having already reached its limit.
 

Noren

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I’ve never heard of blueberries producing potassium sorbate, so I’ll just set that aside.
The smell you’re detecting is H2S, produced by yeast when stressed for some reason. It can be very bad for wine if you don’t get it healthy and fermenting again. If you get rolling, it may just blow it out with no ill effect. If it gets out of control, but you’re able to get dry, it can be treated with Reduless.

I was surprised about the claim that blueberries contain p. sorbate naturally as well. Here are some links that also make the claim: Potassium Sorbate - Ask The Scientists
Wikipedia mentions it as well: Potassium sorbate - Wikipedia (1st paragraph "some berries")
And another one: What is Potassium sorbate | Wine making | Creative Connoisseur

Blueberries can be are very acidic, low in nutrients, and can give yeast fits. I always try to use a yeast with low pH tolerance, raise the pH to 3.35 or higher, use plenty of nutrients, and keep the temps above 75°F. Try getting all of those things in line.
You didn’t mention what your starting SG was, so I’m asking just to rule out the yeast having already reached its limit.

I did add nutrients at the beginning. Maybe the acid was a bit too strong. My starting SG was around 1.060 because I was going to add the sugar in 2 steps. I think that my first attempt (and failure) at blueberry wine last year was that I added too much sugar right at the beginning.
 

KCCam

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have racked it to a new carboy and then also poured most of the liquid out into a primary bucket and splashed it around to try to get rid of the gas. Then I put it back into the carboy and added some Kmeta to counteract any effect of oxygen.
I think at 1.045 the yeast wants oxygen. So splashing in the primary was good because you are giving it oxygen. K-meta is bad because it will stun the yeast, and you certainly don't want to counteract the effect of oxygen: oxygen + yeast + sugar is what gives you alcohol. After fermentation is when you need to keep oxygen away.
 

sour_grapes

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oxygen + yeast + sugar is what gives you alcohol. After fermentation is when you need to keep oxygen away.

Not true. Alcohol production is anaerobic. In aerobic metabolization, oxygen + yeast + sugar = CO2 and no alcohol.

However, the yeasts that we employ exhibit the Crabtree effect. That means that, in the presence of high sugar concentrations, these strains metabolize anaerobically (produce alcohol) even if lots of O2 is around, instead of aerobically (use the O2, no alcohol).
 

KCCam

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Not true. Alcohol production is anaerobic. In aerobic metabolization, oxygen + yeast + sugar = CO2 and no alcohol.

However, the yeasts that we employ exhibit the Crabtree effect. That means that, in the presence of high sugar concentrations, these strains metabolize anaerobically (produce alcohol) even if lots of O2 is around, instead of aerobically (use the O2, no alcohol).
Sorry, so not required for alcohol production, but the yeast does need oxygen, right?
 

KCCam

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Not true. Alcohol production is anaerobic. In aerobic metabolization, oxygen + yeast + sugar = CO2 and no alcohol.

However, the yeasts that we employ exhibit the Crabtree effect. That means that, in the presence of high sugar concentrations, these strains metabolize anaerobically (produce alcohol) even if lots of O2 is around, instead of aerobically (use the O2, no alcohol).
Guess I have some reading to do. I didn't understand half of that article on the Crabtree effect.
 

sour_grapes

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So yeast needs oxygen to multiply, but makes alcohol in spite of it. Huh, Learn something new every day.

Yup, yeast are weird. Just wait until you get to the "haploid vs. diploid" stage of your learning journey!
 

Rice_Guy

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Going back to what @Johnd said, the sulphur smell is indicating the yeast is stressed. The only time I have had that was when running a series of fermentation temperatures. Low temperature as 65F did not produce the problem. But the faster/ hotter fermentation gave the off odor. The correction for stress is to supply a balanced nutrient as Fermaid, or yeast hulls.
When I had the sulphur issue it went away by itself over two months.

i have not seen the secondary algae or gunk issue, at 1.04 you should have low alcohol which opens up the risk of secondary infections.

Your system has alcohol in it! ,,, Adding oxygen in any form decreases the reductive potential. It is likely that you will have some acetaldehyde (oxidized ethanol), resulting in burn flavor in the back of the throat and if high enough level bitter flavor notes.
 
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wood1954

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I had the same problem with my blueberry must. The ph after a couple days was 2.8 and the yeast had stopped working. I added water to get to about 3.5 ph and then pitched fresh yeast. It worked fine. I actually used the lees from that batch to start another batch. Interestingly the first batch of fruit was from Michigan and it had problems, the next batch was from a local farm that uses the bare minimum of chemicals. I think the Michigan fruit had some chemical residue and the fruit wasn’t as good as the local stuff.
 

Scooter68

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With blueberries the biggest point of concern is the pH. As some folks like to make blueberry with ALL fruit and no water - that typically results in a highly acidic must. The pH in that sort of must could even dip below 3.10, NOT the way to start a wine ferment. With blueberries I would want the pH to be at or above 3.20 although you might get away with starting it below that point, you might also have failed start or have it stall out because..... the pH will drop significantly once fermentation starts.
That brings up point 2 - there is no use in measuring the pH after a fermentation has started. Acidity increase sharply during that time.

In your posts I don't see any reference to the STARTING pH or the number of pounds of blueberries/fruit. Having made a number of batches of blueberry wine (about 7 I think so far) I've found that:
1) The sweet spot for flavor and acceptable acidity is at about 5.5 - 7 lbs of blueberries PER GALLON but 7 is pushing the limit with the acidity.
2) A good yeast (NOT Montrachet) will handle a blueberry must with a pH all the way down to 3.18 but that depends on variables I can't even tally up here.

There is no limit to the number of blueberry wine recipes out there but one thing that you need to watch for is
1) The quantity of berries called for - anything with 4 lbs or less of berries per gallon IGNORE IT , find another recipe.
2 Any recipe that calls for the addition of ANY amount of acid or acid blend - IGNORE IT find another recipe. No blueberry only wine should need it.
(Yesterday I saw a YouTube Video about making blueberry wine and it was loaded with incorrect information including the addition of citric acid and the never bothered to measure the pH. There were numerous other errors like referring to StarSan as a sterilizer. (It's sanitizer and there is a significant difference)

Now I want to make this clear - my comments are my personal preference based on my experience. I make single variety wine so my blueberry wine is 100% blueberry no raisins or other juices. (Although I have tried adding about 3 oz of White Grape Concentrate / gallon to a batch with good results in increasing the aroma without affecting the taste.) We all have personal prejudices, likes and dislikes and certainly my posts will reflect that. BUT the pH issue is real and you can find story after story about blueberry wine batches with very high acid levels that had problems fermenting. Typically these issues are reported by folks when they start with the pH below 3.25 approximately.

Altering pH - Unless you used 7 lbs or more of blueberries per gallon, I personally would not add water to the must. I would use a little calcium carbonate. GO SLOW, VERY SLOW with it. If you think it needs 1 tablespoon use 1/3 of that, add, stir and wait at least 8-12 hours. It takes a while for it to really have full effect. You don't want to overcorrect - been there, done that, NO FUN>

As to chemical on the fruit - unless somebody went rogue and used an illegal amount or type of spray on their blueberries before or after they were picked, I really don't think you should see any problems from that. A good rinse of the berries should remove any surface coatings.
 
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