Fermentation Temperatures

I've got a couple of questions. . .

Firstly, when talking about an optimal fermentation temperature range for lagers (I've read between 38 to 59 F) does this refer to the ambient temperature or the temperature of the brew inside the carboy as the yeast is active? How do I compensate for the yeast activity when trying to find the right ambient temperature to submit my brew to?

Second,

Until yesterday, I was unaware of the differences of fermentation temperatures for lager and ale yeast strains. About a week ago I bottled up what I would call a chocolate stout with an ale yeast strain. Unfortunately when I started the brew I was told I could just put it in my basement. It was down there for about a month and my basement was probably anywhere from 38-45 degrees depending on the outside temperature (I'm in Vermont). The airlock bubbled every few seconds consistently for a while, but it never was bubbling every second. After about a month I moved the brew into a secondary fermenter and moved it upstairs in the closet where it remained probably around 50-58 F. Just before I moved it, there was a pretty thick layer of yeast on the bottom of the carboy and throughout the month time the foamy yeast on top dissapeared. It sat in the secondary fermenter in my closet for about a week. When I bottled it, I put a 1/2 teaspon of sugar into each bottle. The brew was subject to more oxygen then I would like at bottling. Right now I have a case in a plastic bucket with a lid by the wood stove (about 60-65 F) and the rest in a box in the bathtub (about 50-58) in case the bottles explode. Can anyone predict what might happen to this brew based on what I've just described? Has the yeast been awakened yet? Is there anything I can do to salvage it ?

I appreciate your consideration

Jon
I can be reached at [email protected]

youve got a lot of info. first off, how long was your stout in the primary at those low temps, secondly how long was it in the secondary at those temps. usually if you had it in the primary for about 2 weeks and the secondary for a week, you should be fine in the bottle. leave it bottled for atleast 14 days. if you only fermented for a few days, you might be in trouble. it really depends on whether your fermentation was complete or not. the only way to tell would be to take a gravity reading. i think if you fermented at those low temps, your brew might be better off fermenting longer. i have heard of stout fermenting at lower temps, it just clarifyes a little better and the taste is a little more crisp.

now as far as your first issue with lager temps. you should ferment a lager at temps between 45 and 55 degrees. usually under 45, the yeast goes to sleep. once youve fermented for about 21 days in the primary and 21 days in the secondary, you can lager in the bottle at 33 degrees for 21-30 days. now, lagering your fermentation temps is tricky. you have to cool the wort to your primary fermentation temps (55f) then let it go through a diacetyl rest for 48 hours. what that means is let it warm up to room temp (70) for 2 days. then bring it back down to 55. remember to bring it down no more than 5 degrees per day or you risk shocking your yeast. then ferment at 55 for 21. rack to secondary, then do another diacetyl rest for 48 hours to room temp. then bring your temp down to between 45-48 for 21 days. remember, no more than 5 degrees per day. after that, bottle and carbonate in the closet for 14 days, then in the fridge and down to 33 degrees for 21-30 days. then youre done. i know that was probably more info than you were expecting, but thats how its done.

Yes, my stout was in the primary for about a month, but at 40 F or possibly even below 40 F, and in the secondary for a week at about 50-55 F.

So for the Lager temps. Do I need to make sure the ambient temperature is between 45 and 55 F or is that the brew itself inside the carboy?

If it is the brew temperature, what should the ambient temps be to make sure the brew temp is 45-55 F?