How do you keep a constant temp, and temp swings?

Discussion in 'Homebrewing' started by slayerhellfire, Mar 8, 2012.

  1. I was just wondering what everyone dose to keep there fermenting home brew at the right temp, I would assume A/C is the most easiest, but I noticed that my oatmeal stout was fermenting away at 67-68 which was great but creeped up to 70 the past 2 days. Would this increase be ruin the brew or when people talk about temp swings it's in greater degrees which can really effect the beer- meaning 65 then to 75 thats a huge difference, thanks!
  2. Usually it would be a quick temp change, like you stated from 65-75. If it is a slow temperature change you might be alright but your yeast can still throw bad things in your beer if fermented at high temperatures.

    I ferment in my basement because it is a constant 62-66 degrees year round. In your case if you can't do that you can do an ice bath, get a chest freezer, etc.
  3. luisfrancisco

    luisfrancisco Savant (335) Mexico Dec 1, 2009 Verified Subscriber

    Ice bath may be too cold. I would adapt a fridge or freezer with a temperature control unit. I actually use a wine cooler and found that the temperatures it maintains are very good for fermentation.

    You could also build a Son of Fermentation chiller, which is what I used to have, but found that changing ice every day was a bit of a pain...
  4. It really also depends on where you live, I live in south GA, so it stays pretty warm year round (had 80deg days in feb!). Northern climates you might be able to get about without anything for 9 months out of the year. Because of the warm temps built my own fermentation chamber using an old dorm fridge, some wood and insualtion. The temps are controlled with a controller. If you think you want to go this route, search homebrew talk forums for fermentation chambers to get some good ideas on how to do it. I wish I had done this in my planning stages, but everything has worked out so well. I just hope I see the results in my brew I have going right now.
  5. Spider889

    Spider889 Advocate (720) Ohio Mar 24, 2010 Verified

    I have brewed some really solid beer without any serious temp control in place. I have found that the ice bath trick is messy and tough to dial in, and I can't afford dealing with the actual chiller/cooler boxes. If my beer gets high for my tastes I will wrap in a wet towel and turn a fan on it - this can drop the temp by 5+ degrees. But even without this, fermenting at room temp has never once caused any off flavors in my beer - just make sure that the ambient temp is not higher than 70 degrees (ie summer with no AC).

    I definitely want to invest in some equipent in this area at some point, but for now I'd say don't sweat it too much. A 2 degree creep with not ruin your beer.
  6. To manage a small amount of temperature change (a few degrees of warming) I have found that simply placing a fermenter in a shallow plastic pan filled with about 4 inches of water performs very well as a ‘heat sink’ and keeps the fermenter temperature at a constant temperature like 68-70°F. I ferment in a half basement and I think this small amount of water encourages the transmission of heat from the fermenter to the basement floor. I am able to maintain a 68-70°F ferment when my ambient temperature is around 73-75°F. If the ambient temperature gets about 75°F then I need to add ice blocks to the water to maintain a 68-70°F ferment. Or an alternate approach is to wrap a towel or T-shirt around the fermenter, let the water wick up and the evaporative cooling maintains a 68-70°F ferment. Under extreme ambient heat conditions I then use a fan to blow air over the towel/T-shirt to provide more oomph to the evaporative cooling.

    This is the plastic pan that I use:

  7. MLucky

    MLucky Savant (390) California Jul 31, 2010

    I bought an old wine fridge on craigslist for $25, and I use that in conjunction with an external thermostat, a thermowell, a brewpad, and a timer. I use the timer to roughly regulate the temp of the refrigerator, which left to its own devices will get down to about 45F. Depending on how cold I want it to be, I set the timer to power off the fridge for several hours each day. I set the carboy on the brewpad, which is hooked up to the thermostat, with the probe in the thermowell. Because the thermostat has a 1 degree setpoint variance, it means I can control temps within a 3 degree range: ie, if I want to ferment at 68F, it can fluctuate from 67-69F. Not perfect, but not bad.

    It's usually considered OK to allow fermentation temps to creep up a few degrees toward the end of primary. In fact, many people do this purposely in order to ensure the yeast stays active to fully attenuate and finish "clean up." There are a lot of variables here, but just for example, you might pitch an ale at 66F, then let it warm to 68 or so as it takes off. At the very tail end of primary, you might let it climb up to 70, maybe even 72. Of course, all of this depends on what kind of yeast it is, what kinds of flavor you want it to impart etc etc etc. I would think your stout will be fine, so long as it doesn't get much over 70.
  8. Yeah it only went up a couple degrees it's constant at 70 right now, I brewed a oatmeal stout with wyeast 1028 so I think it should be fine, will prob start looking in a used fridge or something
  9. mschofield

    mschofield Advocate (655) Massachusetts Oct 16, 2002 Subscriber

    You should be fine, it was in the range you wanted through the yeast growth phase

    The basement of my house is the most temperature stable, but it's too cold for ales right now, and the brew fridge is down there so my real temp control is only suitable for lagers now.

    I have a couple of ales going on the 1st floor, to help maintain temp I have the 2 buckets inside a cardboard box, with large cell bubble wrap filling in the gaps. It's actually working pretty well, between the thermal mass of the 11 gallons of beer and the insultation of the wrap and cardboard
  10. When I need my fermenters to be a bit warmer (a few degrees F) I just wrap then in layers of blankets; fermentation is an exothermic reaction.

    A couple of blankets will keep the ferment a couple of degrees warmer. More blankets, even warmer.