Accidental cold crash with lots of diacetyl

mike_foran · October 27, 2013, 10:32pm

I have a slightly big ale that started like a rocket, but then pooped out when the temperature plunged into the high 50’s one evening. It started at 1.080 and is now at 1.020. The yeast all flocculated and fell out before it was done when it got cold. The gravity is still a bit high and there is too much diacetyl. I put a heater on the carboy and got the temps back up to 68-70 for a couple weeks, swirling it occasionally to get yeast back in suspension, but there is no change.

I am considering pitching new yeast to get it going again. Is this recommended our might it just create more diacetyl at this stage? What is recommended to clean up the flavor?

-Mike

james_rausch · October 27, 2013, 11:19pm

Hi Mike,
Wondering what yeast you used? 1.080 down to 1.020 is 75% attenuation, so the particular yeast strain may be done.
If you want lower, you may have to pitch another strain with higher attenuation, at high kraesen to really give it a kick in the pants.

nighthawk · October 27, 2013, 11:34pm

Extract, PM or AG?

mike_foran · October 27, 2013, 11:53pm

It’s a partial mash, and the yeast is Wyeast 1028 London Ale with a 1L starter.

flars · October 28, 2013, 8:42pm

You could try Fermentis F2. Look up the data sheet, then decide.

mattnaik · October 28, 2013, 8:58pm

This seems to be about the expected attenuation for this yeast. I just pitched some of this into a beer yesterday with an OG of 1.090. I’m hoping for an FG of around 1.021 so this gives me hope that I should meet my target.

mike_foran · October 28, 2013, 10:17pm

Yes, after looking into it that appears to be the case. Thinking of adding the F1 to dry it out and hopefully clean it up a little more.

mike_foran · October 29, 2013, 1:35am

F2 I mean…

denny · October 29, 2013, 4:10pm

The attenuation rating of yeast is meant for comparing one strain to another using a standardized wort. It does not necessarily reflect the attenuation you can expect. Wort fermentability plays a large role in that.

I’d try krausening your beer. Add about a qt. of actively fermenting wort. Works great.

mike_foran · October 29, 2013, 4:20pm

Exactly what I was thinking Denny, thanks!

mike_foran · October 29, 2013, 8:15pm

Denny, do you think I should krausen with the same yeast I started with, the London Ale, or go with the F2 like Mattnaik suggested?

I should note that this is a Christmas Ale, so it should be a little sweet, and I plan to age in the bottle for quite a while.

denny · October 29, 2013, 8:34pm

[quote=“Mike Foran”]Denny, do you think I should krausen with the same yeast I started with, the London Ale, or go with the F2 like Mattnaik suggested?

I should note that this is a Christmas Ale, so it should be a little sweet, and I plan to age in the bottle for quite a while.[/quote]

It really doesn’t matter. IIRC, F2 is a bottling yeast and not really recommended for fermentation anyway. If it was me, I’d go with the same yeast if I had it, and about anything kinda neutral otherwise.