Restarting a 5 month old +1.5 brix stuck chardonnay

[RichB1]

I made the early mistake of transferring a late-fermentation chardonnay from 75 degrees to my 60 degree kegerator, resulting in a stuck fermentation at about 1.5 brix. At the time I brought it back to 75 degrees and added more yeast, without success. I decided at the time to live with it and combine it with a very dry sauvignon blanc to make a sparkling wine. Now I am thinking to give fermentation another try to get it properly finished.

My plan is to make a 1 liter starter in an 2 liter erlenmeyer flask with 2/3 liter stuck wine + 1/3 liter distilled water + yeast nutrient, add red star champagne yeast, then bring it to high krausen on a stir plate over 1-2 days (peak foam/fermentation), then add roughly 1/2 gallon of stuck wine each day to ease yeast acclimation to the already high alcohol level, hopefully maintaining strong fermentation, at 75 degrees.

Biggest questions pertain to oxidation. Currently the stuck wine is in a corny keg under argon, and I have other available kegs. I am less worried about oxidation during the early aerobic stage of fermentation with the base starter in the flask - or should I be?

At that point I am thinking to transfer the starter to another keg, purge with CO2, and then do a close transfer of a small amount of wine each day, pushing it through with CO2 (to save my argon until fermentation is complete). Is some degree of oxygen still necessary at this stage?

I would appreciate any advice or feedback with respect to any part of this process. Should I use double the amount of yeast?

Thank you in advance!
Rich

 

[winemaker81]

If you have active fermentation, oxidation is not a concern. The yeast needs O2 to reproduce, so you want O2 exposure, and once the yeast start eating, it's emitting CO2 which blankets the wine.

What was the OG of the wine? How much wine do you have?

 

[RichB1]

OG was 1.097 and remaining quantity is about 5 gallons.
Good point about oxygen. As long as I am steadily adding wine to a very active starter then the yeast will be in aerobic phase and need oxygen. And there should be at least a minimal amount of CO2 steadily produced as I continue additions (although presumably not much given the relatively low gravity and high alcohol environment).
Thanks for the help!

 

[winemaker81]

How are you measuring the current brix? Hydrometer or refractometer? If you're using a refractometer, note the alcohol skews the reading. If hydrometer, what is the reading?

 

[RichB1]

Hydrometer - 1.006. Despite only being about 10 gravity pts off target, it is overly sweet. When I first tasted it I would have guessed the gravity were much higher. I also appreciate that it seems like a lot of effort to knock of 10 gravity points but for me it is the difference between enjoying it and tolerating it.

 

[winemaker81]

I'm sensitive to sugar and consider 1.006 to be fairly sweeet.

You may be able to simplify the restart process. I use an overnight starter (detailed here), and I can typically smell fermentation in about 6 hours, and have visible fermentation by the following morning.

Your wine is at 75 F, which is good (I ferment between 62 and 70, depending on the current temperature in my cellar), and you're using a Champagne yeast, which has high alcohol tolerance. I don't know if the Red Star version is as robust as Lalvin EC-1118, but I expect it's probably close.

I'd create the starter (as the post indicates, water at ~95 F) and put it next to the must. The starter will cool down to the temperature of the must, so there will be no temperature shock.

Twenty-four hours later, put the wine back into a primary fermenter, swirl the starter to mix, and carefully pour the starter down the inside of the fermenter so it spreads as little as feasible. Put a towel over it and leave it for 24 hours before stirring.

Currently I have four 144 lb batches in progress. I inoculated at 4PM yesterday and could smell fermentation by 8PM. I punched down at noon today (20 hours later), and all containers are fermenting -- 3 of the 4 have high-n-tight caps, the 4th is a bit behind the others. I'm using Avante in two and RC-212 in the other two.

Given the quick start I get with the starter as described, I question the real value of making a more complicated starter. Warm water, nutrient, sugar, and yeast get the yeast reproducing quickly, producing a large colony, and keeping the starter in a tighter area helps the yeast acclimate to the must. YMMV.

 

[RichB1]

I appreciate the helpful advice. Perhaps a standard yeast starter will be sufficiently vigorous to reactivate the fermentation process.
I am curious about the possible efficacy of gradual introduction of the stuck wine to the starter, the premise being that a slightly diluted wine at first helps the yeast to acclimate easier to the high alcohol environment. Maybe the daily additions is overkill, but what about an initial addition of say a quart of stuck wine and then a day later (assuming fermentation remains visibly vigorous) add the remaining 4.5 gallons of stuck wine.

 

[salcoco]

normally it is suggested to add one cup of stuck wine to the starter. once fermenting then add two cups, once fermenting add 4 cups, continue in this matter doubling the volume of stuck wine added to the fermenting wine each time fermentation restarts

 

[RichB1]

Thanks - gradual addition was my original thinking. Glad to hear that others have found it effective.

 

[winemaker81]

@salcoco's advice is good advice. With a 1 cup starter, you're diluting the wine by half and letting it rock. Once you have evidence of fermentation you're increasing the concentration of the wine, but the yeast colony is that much larger. This is proven to work.

I suggest getting the starter going first -- the more ideal (for the yeast) environment of warmer, nutrient, and sugar without alcohol and acid will produce a larger initial colony. Let that perk for 24 hours, then proceed.

 

[RichB1]

Appreciate the help!

 

[NCWC]

Instead of the PITA restart of a fermination. I have recently used this

https://morewinepro.com/products/prorestart-uvaferm-43-encapsulated-wine-yeast-83-1-mesh-bag.html
I had a Cab Franc @1.04 SG and a Zin @1.02. It takes months, but both got down to .997-.996 and taste great