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Sarrsipius · 12-03-2011, 02:00 AM

I made a 5 gallon batch of russian imperial stout with OG of 1.110 last saturday. I used 2 smack packs of 1056 with a 2 litre starter on a stir plate. Starter had blow off and I lost some yeast so I don't really know how much I pitched (don't know how many cells where left in the starter). I used pure 02 in the wort prior to pitching (3 minutes with air stone).

Fermented at 68 and had vigorous fermentaion for 4 days and things settled down by the end of day 6 (today). There are no more visible signs of primary fermentation. Checked gravity and it's at 1.030. This is too high!

Question:
Should I pitch more yeast? What are the pluses and minuses of doing this? If I do re-pitch what yeast strain should I use (more 1056 or a higher alcohol yeast) I'd like it to finish at around 1.020-1.025? I've never re-pitched before so this is new territory for me.

(edit: this is a 5 gal batch)

tdogg · 12-03-2011, 02:05 AM

whats your grainbill? the beer might be done. thats a huge SG and there just might not be any fermentables left. my last RIS finished at 1.030 and i like it just fine!

tdogg · 12-03-2011, 02:07 AM

p.s. if you really want to re pitch, try Nottingham or maybe even champaign yeast.

Sarrsipius · 12-03-2011, 02:33 AM

22lbs Maris Otter
1.5lbs Black Barley (de bittered)
1lb special B
8oz choc malt
8oz rye malt
8oz choc rye malt
8oz charamunich

Mashed at 152

Sarrsipius · 12-03-2011, 02:35 AM

just realized. This is 5 gal not 10. I usually make 10 but didn't have mash tun space in this batch. I said 10 in the original post but that's incorrect. it was 5 gal.

Ozzfest05 · 12-03-2011, 02:36 AM

It may be done.
I good thing to include on these is it done or stalled fermentation threads is your grain bill and actual mash + sparge temp .

Alot of high gravity stout call for ingredients ( specialty grains) which will leave you with high fg. Not only that but you may have mashed above 155 which will extract complex sugars unable to be processed by the yeast, again causing higher fg.

In higher gravity brews pitch rate and proper yeast selection aswell as good aeration ( which you did) makes a big difference.

Ozzfest05 · 12-03-2011, 02:37 AM

Just as I posted you updated with info needed.

Sarrsipius · 12-03-2011, 02:41 AM

the sample was sweet but not overly sweet so if it is done it's not going to be terrible. It may be fine. I've just never had a beer finish with this high of a gravity. I think it would be better about 5-10 points lower. If anyone has any experience with re-pitching after active fermentation is complete i'd be interested to hear your advice.

hafmpty · 12-03-2011, 03:58 AM

I have limited experience with repitching, BUT I just finished listening to an episode of Brew Strong with Jamil Z and John P. If you don't know who they are, Google them. They know what they're talking about. Anyway, they said that if you're going to repitch, don't just pour a new bag of yeast in. Instead, make another starter and wait until it's at high krausen and then dump it in.

One other thing to think about is that with most beers you can expect to drop about 75% of your OG to your FG. That said, you can expect to drop about 82.5 points leaving your FG at about 1.0275. You're really close to that so it might be done.

Not to throw something else at you, but I'm getting ready to brew an RIS that has an estimated OG of 1.123 and an FG of 1.020. That's a bigger drop than 75% which is what you're getting.

If you're interested in listening to the Brew Strong episode here's the link:
The Brewing Network.com - :

Also, they have a four-part series on brewing High Gravity Beers you could check out before your next brew. One other piece of info is the section in How To Brew. Maybe see if it helps.

How to Brew - By John Palmer - Common Problems

Calder · 12-03-2011, 04:44 AM

1.110 to 1.030 = 10.5% abv. You could have reached the limit of the yeast. I know it should be good for more, but it will be struggling at this abv.

Your grain bill has 4 lbs of grain that has a lot of unfermentable sugars (Black, Special B, Choc, Choc Rye, and CaraMunich). This would give you about 10 points of unfermentable sugars. Assuming 10 points, the yeast went from the equivalent of 1.100 to 1.020 with the fermentables, or 80% attenuation, which is pretty good.

I've successfully re-pitched yeast to high gravity beers before, but I'm not sure you would get much more from any yeast due to the high amount of specialty grain you have used.