Adding yeast after 3 week?

[jacketsdb23]

Hi all...

I'm doing an imperial stout that has a target gravity of 1.024. We started at 1.102 and after three weeks its held steady for a few days now at 1.041. I went with an Irish ale yeast (i think wl004 if I remember correctly). My guess is that the yeast mostly died from the ~7.6% ABV. Again recipe stated about 10.5% ABV. The recipe also called for WL001 which may have had a better chance at reaching the lower gravity.

Do you think its too late to try adding more yeast to see if I can push the gravity a bit lower? Adding O2 at this point in the game I'm guessing could alter the taste a bit. Any tips from the pros out there? Thanks!

 

[rsmith179]

You could try repitching some yeast to see if you can get it to attenuate any more. I would not reccommend pumping any more oxygen into the beer now. You'll end up skunking the beer if you do. Before you re-pitch, you may also want to just give your primary a quick swirl to get the yeast resuspended in the beer to see if that helps pick up your fermentation.

 

[janzik]

Would a starter have helped in this situation? Or did it just die out because of the potential alcohol content?

 

[jacketsdb23]

I did a 2000ml starter - it looked really good. The fermentation started within 5 hours and was going very strong. I was really disappointed with the FG. I will try adding the WL001 and let it sit for a few more weeks.

I did stir the yeast after a two weeks and was able to knock the gravity down from 1.044 to 1.041. I finally racked to secondary ( i know, didn't need to but I did ) So now its sitting there and I just want to experiment with methods to improve the attenuation. I'm ok with a ruined beer if I learn from this. I can still count on two hands the number of beers i've tried brewing.

Thanks for the comments!

 

[rsmith179]

A starter may have helped in this situation, but I don't really think that's the issue. Honestly, the attenuation for this beer looks right on with what White Labs has for the attenuation rate of this yeast.

Looks like you have an apparent attenuation of about 75% and White Labs lists attenuation for this strain between 69-74%. The alcohol tolerance for this strain is also listed as Medium-High, so I don't really think the high alcohol content has anything to do with this as well.

If you want to pitch some more yeast, I would recommend going with the US-05 strain to get it down to your wanted FG.

 

[jacketsdb23]

You are right...i guess I should have looked at the attenuation rate for that yeast strain (sorry, rookie mistake!).

I will try the US-05. If it doesn't knock it down a bit more..oh well. I'll still have 5 gallons of beer!

Thanks!

 

[cuinrearview]

I didn't see fermentation temp. noted. You may want to keep an eye on that, even with the 05

 

[ArcaneXor]

I would not reccommend pumping any more oxygen into the beer now. You'll end up skunking the beer if you do.

You will oxidize the beer by adding oxygen. Skunking is a photochemical reaction that has nothing to do with oxygen.

 

[jacketsdb23]

A starter may have helped in this situation, but I don't really think that's the issue. Honestly, the attenuation for this beer looks right on with what White Labs has for the attenuation rate of this yeast.

Looks like you have an apparent attenuation of about 75% and White Labs lists attenuation for this strain between 69-74%. The alcohol tolerance for this strain is also listed as Medium-High, so I don't really think the high alcohol content has anything to do with this as well.

If you want to pitch some more yeast, I would recommend going with the US-05 strain to get it down to your wanted FG.

How did you get 75%? I calculate 60% based on OG of 1.102 and FG of 1.041. Did I do something wrong?

Thanks!

 

[david_42]

60% is correct.

 

[rsmith179]

Yes, I do apologize about the miscalculation there. The 60% attenuation that you got was correct.