Should be a simple primary fermentation question

I'm embarrassed to be asking this question, because I'm a fairly experienced winemaker. My question concerns a persistent primary fermentation, but the SG is not dropping.

A couple of months ago, I received a batch of botrytized juice with a brix level of 35. I'm trying to ferment it to the point that the yeast dies, and I'll be left with some residual sugar. My problem is that it keeps bubbling away (vigorously), but the SG hasn't dropped at all in the last 3 weeks. It's stuck at 1.026.

I've put in a lot of lysozyme, because I don't want MLF. Also, the bubbles "look like" a primary fermentation. There's been a bit of temperature change (I warmed it up a bit up to about 76 degrees) because I wanted to speed things up, but I can't imagine that this is all CO2 coming out of solution.

The yeast that I originally used died when the SG was still in the

1.050 range. That left me with too much residual sugar, so I re- inoculated with Premier Cuvee, which has an alcoholic tolerance of 18 percent. I realize that the Premier Cuvee might ferment all the way down to 0, but that's ok...I can always add back some sugar and be left with a very potent wine. At this point, I just want things to stop.

My alternative is to chill the wine, stop the fermentation, then filter and hit it with sorbate...but frankly, my filtration is never COMPLETELY sterile, and I don't like sorbate.

Any thoughts? This is baffling me. I can understand that the yeast is still doing it's thing. I just don't understand why the SG isn't dropping.

Lee

Reply to
Lee
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You might check the temperature range of the yeast you are using. It may be that it is too cool for it to do its thing the best. It might also be worthwhile to check the pH and adjust if necessary.

I tried fermenting a red outside one year using Pasteur Red. I had a situation like yours (except for the high brix). I then researched and found that Pasteur Red does not like fermenting around 50 degrees. I brought it into the basement and wrapped a heating pad around the fermenting container and introduced some EC-118. It evenutally fermented out. It took over three weeks instead of the usual 10 days.

Reply to
Paul E. Lehmann

Lee

  1. Lysozyme will not stop a full blown MLF once it is in progress. It may have been in the juice when you got it.
  2. Like you, I think P. Cuvee should have a way to go yet but the SG should be dropping slowly to indicate this.
  3. You are already headed toward "Port" style numbers, and if all you want to do is stop it at this point, just add enough alcohol to bring it up to ~20%ABV. This level of alcohol will kill everything (whatever it is) and since high alcohol prevents refermentation, no sorbate will be required. HTH

Frederick

Reply to
frederick ploegman

Seems to me that the key issues are; 1. does the wine have sufficient alcohol already, and 2. is the current activity mlf or yeast?

What I would probly do, in your shoes (which doesn't mean any of it is right!) ....

  • If the alcohol is sufficient at this stage, which it sounds as if it is, refrigerate to stop any activity.
  • Test the RS (I use clinitest) to ensure it is where you want it. Chaptalize later if it needs sweetening ... but I suspect it doesn't
  • Run a paper chrom test to see if there is any lactic acid present - in other words, to determine if the current activity is mlf.
  • If there has been mlf, you can still use lysozyme to prevent any further mlf
  • If there has been mlf, do NOT use sorbate. Use a filtering to prevent further activity, or as someone said, add alcohol - although the resultant wine may be too hot or imbalanced
  • If there has not been mlf, then sorbate should stop any yeast fermentation

Reply to
AxisOfBeagles

How does it taste? If it doesn't taste like you've got bacteria, why not let it go until it is the sweetness and alcohol percent that you like? At 76 degrees you might be getting quite a ferment going. Was the initial ferment cold and slower? If that is what is going on it will probably slow drastically soon.

I have a honey grape I started in August that is still bubbling at the rate of a bubble a minute. It also started very sweet. It tastes good and I am interested in how it turns out. Why rush it? Mary

Reply to
MARY SCHAER

I am making a cranberry now that stuck the same way; it's cold here so I tried making it in the furnace room. The temperature excursions in the room annoyed the yeast. I moved it to a stable temp of ~70F and it picked up in two days and is proceeding down.

Joe

Reply to
Joe Sallustio

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