cold lager

martinworswick · 06-20-2009, 11:43 PM

i tried my first pm lager a few weeks ago and discovered my heatpad was broken (irrepairably), anyway, i managed to keep the temperature reasonably stable for fermenting and then racked to secondary and left it in my garage the temperature for the last week has been swinging a little bit between 0c/32f and -4c/25f (its mid winter here in southern nz)

i'm not really concerned about this as there isn't a great deal i can do about it

but , for educational purposes, how is this likely to affect the finished beer(if at all) ?

i was planning to bottle it in another 4 or so weeks so it may have a few more temp swings before then

BigEd · 06-21-2009, 02:06 AM

Quote:

Originally Posted by martinworswick

i tried my first pm lager a few weeks ago and discovered my heatpad was broken (irrepairably), anyway, i managed to keep the temperature reasonably stable for fermenting and then racked to secondary and left it in my garage the temperature for the last week has been swinging a little bit between 0c and -4c (its mid winter here in southern nz)

i'm not really concerned about this as there isn't a great deal i can do about it

but , for educational purposes, how is this likely to affect the finished beer(if at all) ?

i was planning to bottle it in another 4 or so weeks so it may have a few more temp swings before then

At what temperature was the actual primary fermentation? Typically a lager primary would be in the range of 10-13C. 0-4C would work fine for lagering as long as the basic primary fermentation had been completed. Ideally you want the temperature to remain as constant as possible but a couple of degrees shouldn't be a problem.

martinworswick · 06-21-2009, 02:32 AM

it was 10-12c in the primary, and -4c/ 25f this morning when i checked, i kept it inside the house for primary where i could keep an eye on the temps and then to the garage for secondary and left it to do its thing, we've had a few nights which are colder than usual hence the fluctuations, no freezing that i can see.

if it does start to freeze would it have any detrimental effect?

menschmaschine · 06-21-2009, 03:26 AM

As long as it doesn't freeze, it's fine. But the standard cut off for beer freezing temp is around -2°C. You could wrap it in a blanket or something to minimize temperature fluctuation.

If it does freeze it's not that big of a deal. It may insignificantly affect the conditioning as lager yeast slowly consume minute amounts of sugars during lagering, but that shouldn't be noticeable in the finished beer. It will freeze/drop out all the yeast though, so after thawing and when bottling, you'll have to add 1/4 to 1/2 packet of dry yeast (per ~19 L) to the bottling bucket to get carbonation.

martinworswick · 06-21-2009, 08:42 AM

thanks guys, i'll try to sneak a blanket past the missus for insulating

,

good point about adding yeast at bottling time- i didn't think about that. i assume any yeast is ok at bottling time as its only needed for co2