Temp fluctuations during fermentation

**brewsnthelou** · 02-03-2012, 04:29 PM

I brewed my pumpkin ale Wednesday, starting fermentation looked good yesterday the Krausen had formed, but my temp had become 74 degrees, I was concerned it was too warm to fast and moved it to a cooler location at 66 degrees but it could get too warm there also. Krausen started to dissapate, so fermentation has slowed right? Concerned I still need to find a new location to keep the temps steady, hot, cold, hot, cold can't be good for it, right? I was afraid my basement is just too cold but if I keep it off the floor of the basement and wrap a blanket or two around it would this help? And advice on how to keep these temps steady during this crazy winter in StL would be much appreciated!

Cheers!!

**samc** · 02-03-2012, 05:08 PM

One of the best things you can do for your beer is to build some kind of fermentation chamber. A temperature controller with a used fridge/freezer and a source of heat (light bulb, heating pad, etc.) can be done rather inexpensively if you have the cash. I long ago gave up the issues you are dealing with and the beers just improved drastically.

TheBaconator · 02-03-2012, 05:22 PM

It'll probably be fine. Not to say it wouldn't be better if you were able to pick a temp and stick to it. You probably won't notice any off flavors unless you were to do one right side by side and compare. That being said, high temps contribute to fusel alcohols and generally esters. Depending on what yeast you're using 74 may or may not be that high. But you don't usually start getting really bad stuff until you're way over, e.g. the 80-90 range.

Some fluctuation is bound to happen. Even in a temperature controlled fridge(Although this is really the best way to go). The best thing to do is cool your beer to whatever temperature it needs to be after boiling and then attempt to keep it there. Sometimes you can plan your brew day around the weather forecast if you have a bit of flexibility in when you brew. If it gets too hot you can point a fan at it or put it in a big plastic trashcan surrounded by cool water. You can add ice to that water to get it cooler. If it gets too cool you can put a blanket on it or put it in a room with a space heater. The trash can thing works here too, just set it out in the sun. Make sure to keep an eye on it as it will heat up pretty quick.

Another rule of thumb, it takes about 4 degrees difference in ambient temperature to affect your beer. So if your beer is 74 and you want it to come down, your room needs to be no hotter than 70.

Once your primary fermentation is done, the temperature doesn't matter as much. You still don't want it to get too hot, but fluctuations aren't going to hurt anything.

Hope this helps!

You may check out this thread also.
http://www.homebrewtalk.com/f163/best-way-control-fermentation-temperature-inside-home-161485/

**brewsnthelou** · 02-03-2012, 06:04 PM

Quote:

Originally Posted by TheBaconator

It'll probably be fine. Not to say it wouldn't be better if you were able to pick a temp and stick to it. You probably won't notice any off flavors unless you were to do one right side by side and compare. That being said, high temps contribute to fusel alcohols and generally esters. Depending on what yeast you're using 74 may or may not be that high. But you don't usually start getting really bad stuff until you're way over, e.g. the 80-90 range.

Some fluctuation is bound to happen. Even in a temperature controlled fridge(Although this is really the best way to go). The best thing to do is cool your beer to whatever temperature it needs to be after boiling and then attempt to keep it there. Sometimes you can plan your brew day around the weather forecast if you have a bit of flexibility in when you brew. If it gets too hot you can point a fan at it or put it in a big plastic trashcan surrounded by cool water. You can add ice to that water to get it cooler. If it gets too cool you can put a blanket on it or put it in a room with a space heater. The trash can thing works here too, just set it out in the sun. Make sure to keep an eye on it as it will heat up pretty quick.

Another rule of thumb, it takes about 4 degrees difference in ambient temperature to affect your beer. So if your beer is 74 and you want it to come down, your room needs to be no hotter than 70.

Once your primary fermentation is done, the temperature doesn't matter as much. You still don't want it to get too hot, but fluctuations aren't going to hurt anything.

Hope this helps!

You may check out this thread also.
http://www.homebrewtalk.com/f163/best-way-control-fermentation-temperature-inside-home-161485/

Thanks so much for the info, I appreciate it! I have one of those stick on thermometers on my carboy. I'm gonna try to convert an old refrigerator into my 'fermenting chamber' so I don't have panic attacks everyday! I feel like doc Frankenstein babysitting my creation... Ha

ennis2000000000 · 02-04-2012, 12:24 AM

I just bought a cheap cabinet installed a light balb in the bottom lined the inside with hot water heater insulation and hooked the balb up to a baseboard thermostat

**iaefebs** · 02-04-2012, 12:50 AM

Quote:

Originally Posted by ennis2000000000

I just bought a cheap cabinet installed a light balb in the bottom lined the inside with hot water heater insulation and hooked the balb up to a baseboard thermostat

The first balb I gave you as fast fingered... the second balb I question.

pabloj13 · 02-04-2012, 01:45 AM

Quote:

Originally Posted by iaefebs

the first balb i gave you as fast fingered... The second balb i question.

LOL. I'm with you on that one.

**NordeastBrewer77** · 02-04-2012, 01:49 AM

Quote:

Originally Posted by brewsnthelou

I brewed my pumpkin ale Wednesday, starting fermentation looked good yesterday the Krausen had formed, but my temp had become 74 degrees, I was concerned it was too warm to fast and moved it to a cooler location at 66 degrees but it could get too warm there also. Krausen started to dissapate, so fermentation has slowed right? Concerned I still need to find a new location to keep the temps steady, hot, cold, hot, cold can't be good for it, right? I was afraid my basement is just too cold but if I keep it off the floor of the basement and wrap a blanket or two around it would this help? And advice on how to keep these temps steady during this crazy winter in StL would be much appreciated!

Cheers!!

you really want to keep temps under control and maintained during an active fermentation. take a look at this, it might help ya out on your next batch.

RidingDonkeys · 02-04-2012, 02:23 AM

Brewsnthelou, I had a temperature problem too and found a cheap way to rectify it. While an old refrigerator/lamp setup is best, I just don't have the space for the extra equipment. I ended up finding a way to keep my brew at a solid 68 in a cool room using a reptile heating cord and a timer. Optimal? No. Functional? Yes.

Posted the details here.

http://www.homebrewtalk.com/f11/poor-mans-fermentation-heater-299727/

barleyfreak · 02-04-2012, 05:37 PM

Does anyone know how to calculate how long it takes 5 gallons to adjust to changes in ambient temperature? It is cold in the winter here and my sole source of heat is a woodstove. My last ale ferment had temp swings of 74 at one end and 62 the other. Assuming that the ambient temp was equally divided in both climbing and falling between those two temps, then doesn't it make sense that the beer's temperature would always be playing catch up to those temps and really have a range closer to something like 66 to 70?

In other words if the ambient temp low and high do not stay there for long, then the beer will never actually reach that temp extreme. If anyone knows an online calculator or formula for calculating the change in temp of a liquid in ambient temp changes that would be helpful. I wasn't able to find one.

**Disclaimer** I do understand that ambient and ferment temps are different -- I make adjustments for that.