Stuck fermentation mint wine

[alaskanaturally]

Hi,
We've been making mint wine for years. It works out most of the time but occasionally get a stuck fermentation. This usually happens when it's cold.

We started a recent batch at SG of about 1.085 It fermented to 1.035 and stopped. After a time we added some wine yeast and nutrient. To our delight it started bubbling. That was close to three weeks ago. It's still bubbling but the SG is still at 1.035.

Never had that happen before: A wine appears to be fermenting but the SG doesn't change.

Any Ideas?

Any help would be appreciated,

 

[PandemoniumWines]

What is the temperature of the must? What yeast did you use?

 

[alaskanaturally]

Thanks for responding. On 6/18 the SG 1.085 and we initially added Lavin D47 plus nutrient. Not sure of the temp but had the fermenter wrapped in a heating blanket. It fermented until about 6/23 when the SG was 1.035. On 6/26 we added some DADY and it began to ferment (bubble.) It is still fermenting but the SG has not changed. We've been making this wine for many years and do have a stuck fermentation occasionally. But we never experienced this: Appears to be fermenting but no change in the SG. The ambient temp has ranged between about 68 to 80 so we have not used the blanket. Has anyone experienced this?

 

[sour_grapes]

Thanks for responding. On 6/18 the SG 1.085 and we initially added Lavin D47 plus nutrient. Not sure of the temp but had the fermenter wrapped in a heating blanket. It fermented until about 6/23 when the SG was 1.035. On 6/26 we added some DADY and it began to ferment (bubble.) It is still fermenting but the SG has not changed. We've been making this wine for many years and do have a stuck fermentation occasionally. But we never experienced this: Appears to be fermenting but no change in the SG. The ambient temp has ranged between about 68 to 80 so we have not used the blanket. Has anyone experienced this?

You are interpreting bubbling as evidence for fermenting, but that is not necessarily so. It could just be CO2 produced earlier in the fermentation being released now.

You say that you have done this many times, so I am hesitant to ask this, but let me do so to make sure: Are you measuring the SG with a hydrometer or a refractometer?

 

[alaskanaturally]

Hydrometer. Been thinking about getting a refractometer. Might be worth the investment. We've had CO2 release before but not for weeks. Thanks for your response.

 

[sour_grapes]

Hydrometer. Been thinking about getting a refractometer. Might be worth the investment. We've had CO2 release before but not for weeks. Thanks for your response.

I was not recommending a refractometer; in fact, I recommend against it. You cannot (easily) use a refractometer once fermentation starts because alcohol has a different index of refraction than water does, and so it skews the result. The reason I asked is that a completed fermentation (incorrectly) shows an indicated SG of about 1.030-1.040 on a refractometer.

 

[Val-the-Brew-Gal]

Hi,
We've been making mint wine for years. It works out most of the time but occasionally get a stuck fermentation. This usually happens when it's cold.

We started a recent batch at SG of about 1.085 It fermented to 1.035 and stopped. After a time we added some wine yeast and nutrient. To our delight it started bubbling. That was close to three weeks ago. It's still bubbling but the SG is still at 1.035.

Never had that happen before: A wine appears to be fermenting but the SG doesn't change.

Any Ideas?

Any help would be appreciated,

Is your wine in a carboy or in a primary bucket? Have you tried agitating the wine, either by stirring or by swirling the carboy vigorously? I had two wines recently that, for some reason, slowed almost to a stop around 1.030. I sloshed the heck out of the carboys and they both took off nicely again and finished within about 5 days or so.

 

[alaskanaturally]

Is your wine in a carboy or in a primary bucket? Have you tried agitating the wine, either by stirring or by swirling the carboy vigorously? I had two wines recently that, for some reason, slowed almost to a stop around 1.030. I sloshed the heck out of the carboys and they both took off nicely again and finished within about 5 days or so.

We have it a carboy and have racked it since this happened. Will try shaking it. Thanks

 

[Val-the-Brew-Gal]

We have it a carboy and have racked it since this happened. Will try shaking it. Thanks

I actually tried to introduce some oxygen when I sloshed as I hoped that that would give the little yeasties a boost. Since I was hoping that it would take off fermenting again and push the oxygen out, it wouldn't hurt the wine