Lager temp question

[Syncman]

Brewing my second lager, and temp dropped to 20F in the fermenter before I caught the problem. Saflager 34/70. Just finished 3 days at room temp, and trying to get back to 36F. Any serious problems ahead? Its only a 2 gal batch.

 

[Miraculix]

No.

 

[waldoar15]

If I'm understanding correctly it has finished fermenting, you did a D-rest and cold crashed?

If so, it will be OK.

 

[mongoose33]

If it dropped to 20 degrees F in the fermenter, the beer was frozen. Typo on the temp?

If the beer didn't freeze, and you were cold crashing, you should be fine.

 

[Syncman]

Only 12 hours at 20F, no freezing. Yes, 3 weeks @ 45F, 3 days room temp. Was going to leave 4 weeks @ 36F, but temp went too low. Did not think a mini refrigerator could go that low.

 

[mongoose33]

Only 12 hours at 20F, no freezing. Yes, 3 weeks @ 45F, 3 days room temp. Was going to leave 4 weeks @ 36F, but temp went too low. Did not think a mini refrigerator could go that low.

Do you mean your ambient dropped to 20 degrees? Because beer with 5 percent alcohol--and your lager is likely about that level--will freeze at around 27 degrees (each point increase in alcohol lowers the freezing point by .42 degrees C). So a 5% alcohol beer would freeze around....5 x .42 = 2.1 degrees C, or about 28 degrees F.

It takes my 5-gallon fermenter about 20 hours to drop from 64 to 32 degrees, and all during that time the ambient temp in the refrigerator is less than 32, but because there's a large thermal mass in there it takes time to bring it down in temp.

 

[Syncman]

Only monitoring the refrigerator internal temp. Not the beer, so no idea how cold that got. Definitely did not freeze, so it sounds like I will be fine.

 

[tgolanos]

... So a 5% alcohol beer would freeze around....5 x .42 = 2.1 degrees C, or about 28 degrees F.

2°C is about 36°F; 28°F is -2°C. Would it be more accurate that a 5% beer would freeze at -2°C? Because I've certainly had beer slushies after leaving one just too long in the freezer.