Super stuck fermentation (concord grape wine)

[Frank Bell]

Hello. My dad and I made some concord grape wine again last fall. We've done this for years, and it usually turns out really nice. Last fall, though, we inadvertently added too much sugar. Starting gravity was 1.101 (24 brix). It seemed to be fermenting fine though, but it stopped at 1.039 (15.5 brix). We have the carboys in an area that is between 68-70 degrees. I tried to get it going again by following the instructions shown below that I found at a Midwest Supplies blog. I used the Lavlin EC-1118 yeast. I did both the steps 1 through 4, as well as the 'as a last resort' when the first method didn't work, with about a month between attempts, but the the 'wine' is still at 1.039. Is there anything that can be done to get this going again? Thanks for any advice.

https://www.midwestsupplies.com/blogs/bottled-knowledge/how-do-i-fix-a-stuck-fermentation
How to fix a stuck fermentation

1. Simply move the fermenter to an area that is room temperature, or 68-70 °F. In most cases, too low a temperature is the cause of a stuck fermentation, and bringing the temp up is enough to get it going again.
2. Open up the fermenter, and rouse the yeast by stirring it with a sanitized spoon. Sometimes putting the yeast back in suspension will get it going again.
3. Add some Yeast Energizer to the wine. Add 1/2 teaspoon per gallon of wine, and stir well. NOTE: While it may seem like a good idea, Midwest does NOT recommend adding Yeast Nutrient at this point. This may result in leftover vitamins that can stimulate spoilage microbes.
4. Rack the wine off of the old yeast, and pitch some fresh yeast in, preferably a highly active strain such as Lavlin EC-1118 or Red Star Premier Cuvee.

If none of these tips get the fermentation going again, as a last resort, you can pitch a yeast starter. Do this by pulling a half gallon of must out of your fermenter. Add 1.5 to 2 teaspoons yeast energizer and a packet of yeast (Lavlin EC-1118 or Red Star Premier Cuvee). Stir this mixture up well, and place in a warm area. Once you see a vigorous fermentation, add it back to the original must.

 

[winemaker81]

Welcome to WMT!

Before doing anything else, smell and taste it. It will be sweet, but if it otherwise smells and tastes good, that's a good sign. Note that it's not going to taste like a finished wine that has aged a year.

If you have another packet of yeast, make an overnight starter which will produce a larger initial colony. My method is documented here.

Regardless of the LHBS' recommendation, I'd add a quarter dose of nutrient when adding the yeast.

Is the wine in a bucket or under airlock? If it's under airlock, rack it into a food grade bucket before inoculating.

 

[sour_grapes]

Welcome to WMT!

How are you measuring the SG/Brix? Are you using a refractometer, by any chance?

 

[ChuckD]

If all else fails keep it topped up in bulk and blend it with next years concord. Just make sure the SG is lower next year and ferment it dry.

Or label it a desert wine and tell everyone you meant to do that!

 

[Rice_Guy]

Welcome to WMT

I am a big fan of taste and do action 2 then taste and do action 3 then taste again etc.
Looking at choices I wonder what your pH is. Wine is a food preservation system with low pH keeping many families of organisms out. Even yeast which tolerate acid are struggling if the pH is under 2.8. Alcohol is another preservative and high sugar can also keep some families out. ,,, It is like building a fence. How high do you make your fence (how many preservative techniques).

 

[Frank Bell]

Thank you all very much for the replies!

- Yes, I am using a refractometer to measure and using the Refractometer Calculator at the Northern Brewer site below. It's always worked will with my beer brewing and wine in the past.
- The 'wine' tastes nice, sweeter of course, but no off flavors.
- I just checked the pH, and it's setting around 4.

I'll first try the yeast starter approach and see what happens there. The wine is currently in carboys (three 6.5 gallon carboys), so I'll split into two buckets and try it with one first. If it works, I'll do the other two. I'll post back with results. Thank you!

Refractometer Calculator
https://www.northernbrewer.com/pages/refractometer-calculator

 

[sour_grapes]

Can you try a hydrometer?

 

[Tripled92]

Can you try a hydrometer?

Yeah i would try a a hydrometer as well. Also you can try to use go ferm to help start things back up.

 

[David Violante]

If these don’t work, I’m really liking the recommendation of @ChuckD. If you used a refractometer initially, that number is pretty accurate for your starting point. Putting it in bulk aging isn’t going to hurt anything and it’s going to help your concord to sit a while also. Then when you make your next batch, if you make it less sweet and then when complete blend it with this one, they may balance out nicely. It’s possible once blended, a refermentation could start if there’s remaining sugar from the old one and the possibility of active yeast from the new one. Just something to keep in mind.

You could also drop the acidity a little which would make the perception of sweetness less. I believe @Rice_Guy has mentioned this about soda previously. You have quite a few options really.

 

[Frank Bell]

Hi. Thanks for the added info. I just received more yeast and yeast energizer today, so I'm going to try the yeast starter tonight and pitch it per the instructions. If that doesn't work, I'll try the go ferm. And if that doesn't work, I'll do the 'wait till next year and blend'.

Also, I tested the gravity with a hydrometer, and it came in at 1.030. That's a little lower than the refractometer tested (15.5 brix, 1.039). Is there something about using a refractometer after the initial gravity reading?

I'll post back with results. Thanks everyone!

 

[Ohio Bob]

so I'm going to try the yeast starter tonight and pitch it per the instructions. If that doesn't work, I'll try the go ferm.

GoFerm needs to be rehydrated in the same solution as your yeast.

 

[Tripled92]

Hi. Thanks for the added info. I just received more yeast and yeast energizer today, so I'm going to try the yeast starter tonight and pitch it per the instructions. If that doesn't work, I'll try the go ferm. And if that doesn't work, I'll do the 'wait till next year and blend'.

Also, I tested the gravity with a hydrometer, and it came in at 1.030. That's a little lower than the refractometer tested (15.5 brix, 1.039). Is there something about using a refractometer after the initial gravity reading?

I'll post back with results. Thanks everyone!

I had talked to Scott’s labs a few weeks back (for a totally different reason) and the refractometer isn’t as accurate. I forgot the reason she told me, but the hydrometer is the most accurate system you can use before you get to those $1000 systems that test like everything.

 

[Tripled92]

I had talked to Scott’s labs a few weeks back (for a totally different reason) and the refractometer isn’t as accurate. I forgot the reason she told me, but the hydrometer is the most accurate system you can use before you get to those $1000 systems that test like everything.

Plus i could be wrong but i believe the lowest the refractometers go to is 1.000 so you wouldn’t be able to see the final sg.

 

[sour_grapes]

I had talked to Scott’s labs a few weeks back (for a totally different reason) and the refractometer isn’t as accurate. I forgot the reason she told me, but the hydrometer is the most accurate system you can use before you get to those $1000 systems that test like everything.

The index of refraction of alcohol is different than that of water, which skews the reading of the refactometer. Here is a page with some futher information: http://valleyvintner.com/Refrac_Hydro/Refract_Hydro.htm

 

[Frank Bell]

Thanks All! Here's an update. So, the initial rehydration of the yeast went well, and as advertised, it was active within 30 minutes. I did everything absolutely in accordance with the instructions...except, I forgot to move the wine from the glass carboy to buckets, as Winemaker81 instructed in one of the initial posts, which may in part explain why the fermentation didn't kick off again in the wine. Additionally, I found that the area where the wine is fermenting was about 68 degrees F, but the floor was around 60, which drew the temperature down.

I'm going to redo the process and correct those mistakes. I've already racked the wine into buckets, and I've got the buckets up off the floor. I'll post back later this week after I've got things going again.

Also, thanks much for the info on the refractometer. To be perfectly honest, I am not hugely particular with the absolute final gravity. So long as I know that that it's fermented, even if it's down to 1.000, it will be fine for what I'm doing with my dad. In the end, it's about spending the time with him doing this. And we (generally) get some decent wine out of it.

 

[Frank Bell]

BTW, I also realized that I used Yeast Energizer vice nutrient (such as GoFerm or Fermex). The other instructions I had tried prior to posting here suggested that yeast energizer was the way to go, so I stayed that course (also largely because that's what i have on hand). Should I do yeast nutrient instead?

 

[winemaker81]

To be perfectly honest, I am not hugely particular with the absolute final gravity.

Actually, you don't get to choose the FG, the yeast does. Along with Mother Nature and Dionysus, who are known for getting their jollies out of messing with us mortals.

The SG is considered a measure of sugar remaining, altered by alcohol (which is lighter than water). The truth is that other particles in the wine have an effect, so the FG will typically vary from 0.998 to 0.990. Reds often have a higher FG than whites due to differences in composition. Also note that while we generally accept 0.998 as the upper bound, on rare occasions a wine will end higher.

BTW, I also realized that I used Yeast Energizer vice nutrient (such as GoFerm or Fermex). The other instructions I had tried prior to posting here suggested that yeast energizer was the way to go, so I stayed that course (also largely because that's what i have on hand). Should I do yeast nutrient instead?

Energizer is a different entity than nutrient. Think of it as speed (amphetamines) vs. food. Speed will amp you up, but you need food for energy. This is not a 100% correct analogy, but it hopefully conveys the concept.

Fermax and the various Fermaid products contain nutrient (minerals, etc) that yeast need in addition to food for it, so I generally use this type of product.

 

[Frank Bell]

Excellent info! I got the FermGo yesterday and have the rehydrated yeast acclimating in the fermentation area now and will be adding it to the bucket this evening. Currently 68 degrees in the area. Thank you!

 

[Frank Bell]

Hi All. Thought I'd give you an update on this. Just checked the gravity again (with a hydrometer), and it's still at 1.030, i.e., no change. It does taste ok, just not completely fermented, which is perplexing. So, it looks like I'm left with the option to hang on to it until next year, make some dry wine, and then blend it. In the meantime, it will be like drinking a session IPA. A session dessert wine.

Thank you all for your time, experience, and consideration to post and try to help me! I greatly appreciate it!