Long fermentation

[Mark Farrall]

I've had a Russian Imperial fermenting for about six weeks now. About five days in things were going well, it was at about mid-40% attenuation of an expected 80%. Then the fridge lost power and the temperature dropped and the fermentation would restart. I tried pitching more of the US-05 that I was using and it would restart.

The LHBS recommended the White Labs WLP099 High gravity yeast. I pitched that and the fermentation started back up. Then it slowed down at around the high 60% attenuation (not surprising as I'm pretty sure I let the mash get too hot and thought I'd have a fair bit of unfermentable sugars). From then it's just been dropping 1 gravity point every 2-3 days, to the point where I'm now at 73% attenuation.

So I'd be happy to bottle considering I thought it was going to be much worse and I'm nearly at 11% ABV, but the gravity just keeps dropping. It turns out that this yeast is one of the diastatic sacchromyces strains, so it's actually fixing up my mash problems. So I'm not keen to bottle while the yeast is going to keep breaking down sugars and possibly create bottle bombs.

So I'm expecting that I'll leave it in the fermenter to just keep chewing away at the sugars until it stops moving. Is that opening me up to any other problems that may mean bottling is the lesser of two evils?

 

[BOB357]

I was going to offer some very different advice until I read that you'd repitched with a diastaticus strain. Sorry, but all I can say now is this looks like a well botched batch. I would , however advise that you transfer it off of the yeast and when you decide to bottle, put it somewhere that bottle bombs won't do any damage. Good luck!

 

[Hogarthe]

I say leave it till it stops losing gravity points. Blowing up bottles isn't worth it.

 

[BOB357]

Agree, but after more than 6 weeks it really needs to be transferred off of the yeast. From what I've read about diastaticus strains they can appear to have stopped and then restart fermentation. With the yeast cocktail in that batch, I wouldn't know what to expect, so would put the bottles in a safe place either way.

 

[Nosybear]

I say leave it till it stops losing gravity points. Blowing up bottles isn't worth it.

Second that. And next time you're making a high-gravity batch, remember to give it oxygen twice, once before pitching and once about 18 hours later. That'll help the yeast through a very stressful fermentation. And be sure you're pitching enough.

 

[sbaclimber]

It turns out that this yeast is one of the diastatic sacchromyces strains, so it's actually fixing up my mash problems. So I'm not keen to bottle while the yeast is going to keep breaking down sugars and possibly create bottle bombs.

So I'm expecting that I'll leave it in the fermenter to just keep chewing away at the sugars until it stops moving. Is that opening me up to any other problems that may mean bottling is the lesser of two evils?

I'm with Hogarthe here...leave it!
Unless you can kill the yeast at bottling, you are risking bottle bombs. Not to mention, even if the bottles don't blow, you will be waiting forever for a stable beer. Let the yeast do it's thing in the fermenter.
I don't bottle early, but there is still a lot that happens in the first 4-6 weeks in the bottle.

PS...cross-posted with those above...who probably have more experience...
meh, good luck with what you've got!