Stuck fermentation - how long to leave it for?

Porter, sitting at a steady 22 degrees, should be 5.2% abv, fermentation stopped at 2.5%

A stir took it to 3.5% over a week.

Added yeast, and nutrient, no sign of further fermentation 2 days on.

Should I leave this, how long for? or can I try something else to coax it up to 5.2% ? Somebody suggested kegging and just leaving it, ideally I'd see this brew through to bottling in next 5 days as wish to free up my brew bucket for the next xmas brews.

Topic porter stuck-fermentation yeast homebrew

Category Mac


Seeing how your beer is at 22-23 degrees, I think the issues are more yeast related. Rousing the yeast one more time to see what you get might be your only option. I usually let the beers I brew go for two weeks, often three, before I check them.

You could try and get a small active starter going with some fresh yeast. Say in a growler with a 1.030 DME based wort. Once that comes to a krausen point pitch the whole thing in the beer. Pitching dry yeast alone into a beer really doesn't get it moving again too harsh an environment on the dry yeast.

Normally, I'd just say chalk it up to a loss and bottle it. Just be vigilant that the bottles don't over carbonate and become a liability.


I'd heat it up for a while. In general, you do get better quality if you wait it out at a lower temperature, but if it's a question of whether you get the next brew down or not, and your brew is currently not moving at all, then it seems worthwhile.

What I do is to just run hot water into the laundry tub with the brew bucket sitting in it. You can easily boost the temperature to 30ish degrees for a few hours this way, which usually gets the brew moving. Sometimes I have to do it a couple of times.

I presume it does cost you some of the aromatic compounds, but a porter is a pretty robust sort of beer, so I wouldn't worry too much.

It's very often the case that your sugar is not properly dissolved and is sitting on the bottom. I brew in glassware, so it's easy to see that. You might find that giving your brew a good slosh around helps. My approach is to get a circular motion going, and keep that up for 5-10 mins.

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