Fermenting at unstable temperatures

[sebbb]

I'm considering to start brewing in my flat soon. However, my house temperature isn't stable as the the heater only works during the night hence being colder during the daytime.
I'm not sure what the specific temperature difference is, but I image it's at least 5 to 7 (°C).

Is there any way I could manage to have a batch fermenting succesfully even in these conditions?

 

[hottpeper13]

I like fermenting on the cooler end of the recommended range,so first you need to be able to get to that temp. Then keeping it within 2*F is the best way to get a clean fermentation. with that in mind I put the carboy in a cool spot,easy this time of year as my basement is 55*,put a heat wrap and blanket around it with a temp controller. At least wrap it so it stays consistent temp. Maybe you'll have to wait till after the initial start where the exothermic heat generated will push up the temp. After 5 or 6 days raise the temp to the higher end of the range to finish and do a clean up.

 

[flars]

Having the fermentor in a tub of water is the easiest way to protect it from the changes in air temperature. Yeast as it ferments the beer will produce some heat. The water will absorb some of this heat preventing rapid temperature rises inside the fermentor during the fermentation.

You may need to heat or cool this water depending upon what temperature the tub of water will stabilize at and the optimum temperature range of the yeast you plan to use. The temperature of the water in the tub may also stabilize at the perfect temperature without the need for heating or cooling.

Experiment with a large volume of water. Check the temperature over a period of a few days. The largest kettle you have may suffice for this experiment.

 

[evchenko]

You could also take a look at different kinds of yeasts, one that would work fine with the temperature swings.

Mangrove Jack's Workhorse for example:-

"Suitable to ferment lager styles at 15-20°C (59-68 °F) and all other beer styles at 20-32°C (68-90°F)."

 

[JohnSand]

And if you brew five gallon batches, the temperature of the wort will not change as fast as the air. A closet may be more stable than a big room. Keep reading and thinking, you'll find a way.

 

[GHBWNY]

Having the fermentor in a tub of water is the easiest way to protect it from the changes in air temperature. Yeast as it ferments the beer will produce some heat. The water will absorb some of this heat preventing rapid temperature rises inside the fermentor during the fermentation.

You may need to heat or cool this water depending upon what temperature the tub of water will stabilize at and the optimum temperature range of the yeast you plan to use. The temperature of the water in the tub may also stabilize at the perfect temperature without the need for heating or cooling.

Experiment with a large volume of water. Check the temperature over a period of a few days. The largest kettle you have may suffice for this experiment.

This^ absolutely. I still use this method in my sometimes-not-so-stable ambient conditions. In the winter, the cellar where I ferment stays at a stable 62F, which is ideal for most of my ales. In summer, it gets up to 70-72F, which is when I employ the swamp cooler.

Piggybacking on what flars said, a large plastic round or rectangular tub that will easily accommodate your ferm vessel also works well. The larger the volume of water, the less chance of temp fluctuations. Start by setting your fermenter in the tub and fill with water a few degrees shy of recommended ferm temp, e.g., if your recommended ferm temp is say, 68F, fill tub with water @ 62-64F, and up to as near the level of the wort in the fermenter as you can. Why cooler than ferm temp? There will be an exothermic reaction (rise in internal wort temperature) of anywhere from 5-10 degrees F from the yeast activity, and a stable temp is critically important at this point. I keep some frozen water bottles on hand in case I need to bring the temp down. I also drape wet towels over the fermenter, letting the ends sit in the water. Works like a charm. Slow and cool.