Cold spell, need opinion

I started fermenting out a British Specialty Ale (essentially a Belgian specialty ale except with Fermentis S04 yeast) in my garage in my freezer with temp controller set to 60 *f. about a week ago last Sunday. This chest freezer is in my garage, in a sheltered spot very close to the interior of the house.

It appears that the krausen has fallen and fermentation is starting to slow. I'd like to let the beer continue to sit in the primary for a full three weeks for a nice diacetyl rest and for the yeasts to consume all of the off flavors and alcohols. However, last night we had a cold snap that drove outside temps down close to freezing levels. I checked the brew's temp (liquid crystal thermometer glued to the glass carboy exterior) and it's comfortably at 64 *f inside the chest freezer.

My concern is, as fermentation slows down, the beer is going to gradually begin to cool off. I'm worried the drop in temps is going to slow down the diacetyl rest. The ambient temps in the garage are in the lower 50's and there is some insulating factor having the beer inside the chest freezer.

What i'm asking is, if it were your beer, would you move the beer inside for the final two weeks of conditioning?

If it were my beer, I would cover the fermentor with aluminum foil, and set a small desk lamp inside the freezer. It will generate enough heat in a close environment to raise the ambient temp by a few degrees, and the aluminum will keep light out of your beer.

HOWEVER: I have a simple PID controller that is connected to a thermometer. This means that I can set the temp on the controller, and when the beer reaches target temp, the controller will turn off the lamp. When temp drops off the temp, the lamp will get turned back on. If you don't have this option, you need to check your beer temp often to make sure it's not getting too hot.

But to answer your question: No, I would not move the beer. But that's as much because I'm lazy as it is because I don't want to move it.

I think the desk lamp that was suggested is a good idea, especially if you can hook it up to your temperature controller. I did this, this last week and it worked very well. Just use a small wattage bulb and check it frequently if you don't have a temp controller.

If using a lamp is not an option, there would be no harm in moving your beer inside. That is a good worry free option.

Just wondering if moving the beer indoors at this point will have any negative effects?! Again, the krausen has fallen and the fermentation has slowed immensely. I'm sure it's not done quite yet, but will moving it into a warmer 70 degree house do anything adverse to the last two weeks of fermenting?

Moving it into a 70 degree house should not have any ill effects as long as the fermentation is mostly over and as long as you shelter it from light while it's sitting inside your house, a black trashbag out to do the trick. If you're worried about diacetyl, the 70 degree atmosphere will definitely speed up that diacetyl rest. I've never used S04, but for most ale yeast 48 hours or so (post fermentation) should be more than enough for a satisfactory diacetyl rest at high 60s low 70s.

Drop in a heating pad set on high in an empty area. I just did this this morning for my diacetyl rest. I have a one stage controller so it will cool back down, if needed.

After ten days of fermentation, I'd think that not only would going inside to 70F not hurt your beer, it might even conceivably help the yeast finish any remaining activity. I regularly ferment my pale ales at 63-65 for about a week, then move them to a closet at about 70. Off flavors [edit:] caused by too-high fermentation temps [/edit] tend to arise in the first day or two of active fermentation; after that are not much of a threat IME.

To me, better safe than sorry... although I also love to tinker with stuff and would probably move on the lamp idea for future use if not for this batch

Leaning on moving it indoors at this point. Thanks for the input, guys.

OP thanks for this post. Lot of great responses and made me feel better about a similar situation I was in. I put two fermenters in my garage to ferment, after 5-6 days in a cool garage (low 60's in the day and mid 50's at night) I checked gravity and it had reached final. I was worried the garage would be to cold after aggressive fermentation completed and brought them inside. Sounds like I did the correct thing. Thanks for posting your question, the responses put my mind at ease.

NP, just worried that moving the fermenter indoors might've produced off flavors in the beer. Been doing some reading, and a lot of styles will gradually step up the temps on beer as the fermentation slows to help the yeast stress less and attenuate more of the maltose/sugars out of the beer and help consume some of the fusel alcohols produced during primary fermentation (if present).

Update: I moved the carbouy inside. It's churning right along at about a bubble a second through the airlock.