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Old 08-01-2012, 06:45 PM   #1
Jan 2011
Indianapolis, Indiana
Posts: 669
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I made 5 gallons of a chocolate mulberry port back in June. I used Pasteur Red yeast (16%ABV tolerance) and fed the wine with equal amounts of sugar at three 10 day intervals. I can't be 100% sure of the expected FG due to varying sugar in the fruit and general innacuracy of the scales on buckets, but the wine should have hit its alcohol tolerance at about 1.016-1.024 FG.

After 5 weeks in primary, I checked the gravity and it was at 1.032. I pitched fresh yeast in a 16 oz sucrose starter with nutrient. After 2 days I decanted and siphoned off about 16 oz of the wine. After another 2 days I pitched that back into the wine.

Two weeks later and the hydrometer has not moved a bit. I'm at a loss for how to proceed to get this fixed. My first instinct was to make a gallon of the wine and rack the other 5 gallons onto that yeast cake, but what if the wine is stuck at 1.032 FG no matter what?

Then I wondered if I could just make a second smaller batch, let it finish dry and then blend at bottling. For example, if I blend 5 gallons of 1.032 wine with 2 gallons of 0.992 wine I will get 7 gallons of 1.020 wine. Would that work?

Any other ideas I haven't thought of would be great, too.

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Old 08-01-2012, 11:01 PM   #2
Sep 2011
Posts: 1,174
Liked 270 Times on 201 Posts

1.032 is pretty sweet, but does it taste satisfactory? You could probably just keep it as is or fortify and/or spice it etc or blend it as you mentioned ... that’s what I’d probably do.

In any regard ... if you really want to reduce the residual sugar further ...

Pasteur Red is not a yeast that is overly prone to getting stuck.
I’d think you got stuck possibly due to a couple reasons.

Without having a reasonable estimate of your ABV there is the chance that you have simply exceeded the yeasts alcohol tolerance. In which case if you are going to re-start the ferment ... make sure the must has settled reasonably, rack it off the lees and pitch another starter using a yeast with higher ETOH tolerance.
(restarting is particularly desirable if you added much additional nutrient late in the ferment - or in an attempt to get it unstuck - without successful additional fermentation to utilize it.)

Considering the extremely long time your must had been fermenting in the primary (and btw I assume you are now using a covered primary with an airlock!); unless one is using a yeast and temperatures specifically intended to extend the primary ferment for a long period, you may have created an unhealthy, slow yeast culture.
Considering your sugar additions ... as sugar increases in solution there is a point where the stress and mortality of the yeast increases because osmotic pressures dehydrate the yeast cells. This can result in a further stressed and problem yeast culture which takes much longer to ferment out. Without having kept close and accurate track of SG this may be part of the problem.
As well, in general you should have been adding nutrient and nitrogen additions (DAP) during fermentation alongside your sugar additions.

Also yeast should be re-hydrated properly in straight water prior to using it in a starter to maintain as high a count of healthy yeast as possible.

Assuming you do have the must under airlock .... at this point I’d do a few things ...

Double check pH to make sure a pH drop did not stall the ferment. If it was pH that stalled it ... fix the pH and restart the ferment.

For restarting the ferment ...
So that you do not have to add additional nutrient with such a small amount of distance to go until your target SG, use a yeast that has low nutrient requirements such as EC-1118.
Re-hydrate the yeast properly in straight water.
Siphon from the primary an amount of must sufficient to create a starter and add some additional sugar to it (up to a typical OG) ... get the starter going. Rack the must to a new open top primary fermenter (bucket) leaving all the lees behind. ... give it a good vigorous 4 minute stir (or shake) and use your new starter to re-start the batch. Once fermentation re-starts move it promptly back to a carboy and under airlock.

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