Stuck fermentation?

[peterg]

This is my second attempt at winemaking. I'm using fresh grape juice (cabernet sauvignon from California) and Lalvin D80 yeast with Go-Ferm and SuperFerment nutrients. Started fermenting in a FastFerment conical fermenter and everything seemed to be going well for the first few days. When I got down to Brix of 2.1 on Day 5, I discarded the gross lees from the FastFerment's collection ball and racked into a glass carboy. Things radically slowed down after that and now I fear they might be stuck. Here is my log so far:

Day Temp Brix
1 61.7 22.8
2 74.8 15.8
3 74.4 6.1
5 72.3 2.1
7 71.6 1.1
8 1.1
10 0.8
12 73.4 0.8

I do see extremely tiny bubbles still rising, but very few and very tiny. No action in the air lock. And I feel like the must has an off odor although I really can't describe it. It is not vinegar or rotten eggs or other things I've read about, just seems not quite right (at least from what I remember last year).

Should I be patient and give it more time, or consider taking some action like re-inoculating with more yeast?

Thanks in advance for any advice!

Pete

 

[NorCal]

I’d be patient and see if it finishes on its own, restarting Wine now would be very difficult. As a rule, I don’t rack off lees above 1 brix and will only do so that early if the fruit was in bad shape, or I sense H2S.

 

[Turock]

I agree with NorCal. But the other thing I'm thinking is if you divided your total nutrient amount in half and pitched the second half when you got to 1/3 sugar reduction. Yeast can run out of nutrient half-way, or so, thru the ferment and without more nutrient, the ferment can get very sluggish. Pitching nutrient up-front ONLY can often be the cause of such a problem.

 

[skeenatron]

Do you have any other fermenations going right now?

 

[peterg]

Hi all -- thanks for feedback -- sorry for my slow reply. I do think it is stuck now -- Brix has not budged in 4 days and everything appears still now.

NorCal did racking too soon end up removing most/all of the viable yeast?

Turock nutrients could indeed be part of the problem. I used Go-Ferm (yeast hulls) only at inoculation and added the SuperFerment (containing DAP) after about 24 hours, but didn't use the full recommended amount of the SuperFerment. I had read some things that were negative about DAP.

skeenatron I do not have any other fermentations going on.

What can I do to try to restart? Can I just try inoculating again with fresh yeast?

Thanks for the advice!

 

[peterg]

PS -- I do think there is an off odor, as well, but it doesn't seem like any of the odors I've read about (e.g. rotten eggs for H2S). I can't really describe or put a finger on it, but it doesn't smell right.

 

[skeenatron]

I think your best bet is to get some stronger yeast in there asap. Ideally I'd say get the lees from an active fermentation that is just about done, because it's acclimated to the hostile, alcohol laced conditions. Since you don't have that, you're going to need to use fresh yeast. I highly, highly recommend Uvaferm 43 Restart. If you can get your hands on some of this asap and reinoculate, you may be able to get through.

http://www.scottlab.com/product-425.aspx

 

[peterg]

Thanks -- will give it a try. I will have to see if I can find the Uvaferm somewhere. The only thing I have on hand is Red Star Pasteur Red which appears to have an alcohol tolerance of 15-16%. Not sure about nutrient requirements. Do you think it would be reasonable to try?

 

[skeenatron]

Worth a shot if you have it on hand. The strain makes a huge difference though, and I can't vouch for that one personally.

 

[peterg]

Reading more, it sounds like trying to restart is pretty complicated and could have a very limited chance of success. Should I consider just stopping and trying to stabilize it and make it a sweeter wine? I'm at 0.8 Brix now. I had also planned to try MLF -- would I need to abort the MLF if I stop here? I had overcorrected the acid some, anticipating that pH would rise some with MLF.

Could I make port from here??

 

[skeenatron]

Don't know about the port ideal, never done it. The restart protocol with the dilutions and mother tanks and all that is very complex I agree. I'd be weary of doing MLF with that amount of sugar left but you are definitely running out of options I suppose. The extra acid could make a sweet red better though, maybe leaving it be is the best solution. The longer it goes without sulfur or some sort of fermentation protecting it, the more gnarly flavors will develop.

 

[peterg]

Thanks - really appreciate your advice!

 

[skeenatron]

Hope it all works for ya man!

 

[Ajmassa]

It shouldn't taste that sweet tho. If you went from 22.8 Brix to .8 your at 12.14% abv.
If you got down to 0 Brix it would only bump to 12.75% abv.
If left alone I think it could still be a good easy drinking Cabernet. Just not as dry or BIG as it could hav been. But that is not necessarily a bad thing right?
Odor may just be extremely young freshly fermented wine that needs to be cleaned with racking and age.
And what risks are involved with the MLF? I don't know the science behind having a small amount of residual sugar in there during MLF, but is it any different than the sugar present when malo is inoculated at the beginning of fermentation? Because I've done that without issue.

 

[peterg]

Funny but I just decided to taste it and was pleasantly surprised. It's rough of course, but no "off" taste of spoilage or anything. I think you might be right that the odor I was noticing was nothing abnormal/pathologic -- my wife thought it smelled fine. Pretty strong alcohol taste, a little bit of sweetness but not too much. I think the most noticeable thing was pretty harsh acidity (the pH is about 3.25 right now). Maybe it would do okay as is with maturation but I'm worried it would remain too acidic. I am tempted to try the MLF.

I also reread the restart protocol found here (http://www.scottlab.com/uploads/documents/downloads/136/2016RestartStuck.pdf) and thinking maybe it isn't too hard and I should give it a shot. I can order the Uvaferm 43 online, although can't find the other "Reskue" product anywhere. I'm only working with 5 gallons so my "mother restart tank" would just start as 40ml in a beaker. I have an empty 3 gallon carboy and could do the 10% stepped additions into there before returning it all to the main carboy. It seems a little less scary that way than when reading about pounds and hectoliters and such. Would I be running a risk of way too much oxygen exposure, though? I don't have any gas to protect with.

 

[peterg]

BTW I'm bummed this happened but it is kind of fun to try to figure out what to do.

 

[AkTom]

Being a newbie wine maker... and it's only 5 gallons. If it were me, I'd rack half of it, leave it. The other half I'd play with to see what I could do.
Cheers

 

[Ajmassa]

I'm in the same boat right now. And you've definitely got the right mindset. It's tough with such a low Brix to restart. So I'm doing everything I can to help it out. Instead of Reskue I added lysozyme and will also add yeast hulls before racking and attempting the restart.
I'm sitting at 12.75% and 1.001. Only difference is it's already completed MLF.
If I get it lower after all that work then great. If not, no big deal. It still tastes very promising. And will have learned a bunch in the process.

Correction. Reskue is interchangeable with the standard yeast hulls -Not the lysozyme, which is being used for some protection against bacteria instead of adding so2 which could inhibit yeast from restarting.
Though that point might be moot, and sounds like you might be pushing on as is. Either way, good luck.

 

[NorCal]

.8 brix? I wouldn’t do a thing. The best wine I’ve made (from those that drank it) was a .6 brix stuck, but stable Grenache fermentation. I’d call it a blessing, make sure it’s stable and bottle a wine that will be enjoyed.