Brewing temperature swings

[Rob Martin]

What is a safe temperature swing for lagering? For instance, if a storage facility swings from 41-47 and back within 24 hours, is that too much? While the air might swing 6 deg, would 5 gallons really swing more than 2-3?

[klickcue]

Are you talking about lagering as in fermenting or as in aging?

If fermenting, I would look at the yeast spec to see what range the yeast will work in. I ferment my lagers (White Labs yeast 820, 830 and 833) at 50 degrees which is the low end of the temperature range. Generally, they are done in a month or so since the yeast works slower at lower temperatures. I check the terminal gravity as well as by feel.

If aging, think of the ice houses or caves of Germany. Cave temperature might be about 50 degrees and ice houses about 34 degrees. If you are aging, you are well within the range.

What lager style are you working with? Lager yeast is an interesting bug.

[Rob Martin]

I've successfully fermented with Saflager W-34 as low as 44, but it was stable give or take 1 deg. I was concerned about the daily swing of 5-7 degrees and how that would affect fermentation in general.

Thanks

[klickcue]

I don't think that it will make much difference since you are below the fermentation temperature zone for the yeast. It will just take longer for the fermentation to complete. If you started with cold wort, you most likely will not have to raise the temperature for a diacetyl rest.

If we look at bread yeast, the lower temperatures add more flavor to the bread as well as a finer crumb.

[klickcue]

The range of attenuation of your yeast is 73-77%. Assuming a SG of 1.047 SG then your final gravity will be as follows.

(SG * (1 - Atten)) = final

(47 * (1 - .73)) = 1.013 SG
(47 * (1 - .77)) = 1.011 SG

All in the love to kick back and enjoy life!

Let us know how your brew comes to final.