Stuck Fermentation

[OGBrewer76]

Hey Forumites,
So we had some rolling blackouts for a solid week and not sure if that caused my stuck fermentation or not. Regardless, I have a stuck fermentation. I went ahead and pitched in more freshly harvested yeast once I noticed fermentation was stuck and nothing happened. So thoughts on how to get it to finish out? SG was 25P, current gravity is 10P. I need it to go to 4-5P.
Thoughts?
Thanks
J

[Jeffhorn83]

You could always try heating it up, and re-oxygenating it in line as you do it

[dick murton]

You don't say if this is the first time you have brewed at this gravity. Most yeasts (well OK, those in my experience) require supplementary oxygen in the early stages of fermentation but stop additions at about 10 P to allow diacetyl production to be mopped up, and minimise excessive yeast growth.

In this case, as suggested, "fresh" yeast and a good blast of air / oxygen - and pray.

When brewing barley wine, I was lucky that we brewed several times a week, so had plenty of opportunity to blend away any problem fermentations. More recent attempts in micros have proven a bit more awkward as the yeasts have been different in every brewery, so not sure how an individual yeast strain will respond.

[UnFermentable]

I'm sure you've already taken a course of action on this beer, but to add to the comments below:

Using "fresh" yeast is highly recommended, but on a beer this big you are fighting an uphill battle. I would suggest you make some starter wort to add the fresh yeast to. Once it is at high krausen, then add it to your stalled batch aerating heavily. With the alcohol present and other factors, you will be lucky to see a significant drop in gravity before the yeast dies out. You could also krausen from another batch of beer, if you have one that can be blended with the stalled batch.

I would drop the old tired yeast before pitching new, and raise the tank set point at least a few degrees higher to make sure jackets don't switch on.

I sincerely doubt the blackouts would have been the cause of this, unless you have glycol solenoids that are default open. We have power outages here at least weekly and if anything the temps rise slightly and the beer ferments more rapidly. Even after a few hours tank temperature rise little, and we may see .1 or .2*P lower final gravity.