Using an Unpowered freezer as fermenting chamber

Hey all,

So, I have a spare smaller chest freezer kicking around. I would like to use it as a fermenting chamber. Now, seeing as I live in frigid Canada, and it is coming up on winter, I am wondering if it will work for this purpose and be able to have stable temperatures naturally. The temperature in the house ranges during the day from 17 (62.3) to 23 (73.4) depending on whether we are home or not. The freezer sits in a very poorly insulated addition of the house we rent.

Ideally, I am hoping that the insulation of the freezer would resist the ambient temp swings and keep things fairly consistent.

Ideally, I'd like to not modify the freezer or use a temp controller for cost savings, and honestly, use the naturally cold Canadian winters to help me out with the process.

Any thoughts to this? Would the CO2 and heat given off by the yeast increase the temp in the freezer constantly and counteract the whole concept?

In a way yes, and in a way no. What you gain by using an insulated fermentation chamber--such as your unpowered freezer--is a small closed system. As such, you have less temperature fluctuations from external temperature variations (e.g. the temp of your house) but greater temp fluctuations from internal temperature sources (e.g., heat put off from the yeast, a lightbulb, etc.). So, if left empty, your chamber would probably stay in a tight range somewhere in the median temp of your home (say 67-68 or so). That is a great temperature target for fermenting ales. However, if you put your fermentor in the chamber, you will likely see a fairly large temp spike due to the heat production by the yeast and due to the fact it is in a small enclosed system. The temps would then likely stay fairly high (probably near your max house temp of 72), as the freezer insulates against the colder outside temps. With a bit of experimentation, however, and given the colder temps approaching, you could perhaps get your interior temps to stabilize lower, then have the natural temp rise hit your ideal temps.

You could totally make this work while it's cold outside. Just use a temperature controller (like an STC-1000) wired to a tiny heater and fan. You can set them to kick on when things are getting too cold.

I have a small freezer in my shed with a temp controller like the STC1000 and now that it is getting cooler it will get too cool inside even turned off. A small heat wrap around the bucket and a temp probe inside the wort works great.

This winter I plan to use a broken fridge in my garage to ferment lagers: I'll put a fermwrap around a carboy and use a Ranco controller to bump the heat up from an ambient 35F or so to 50F.

I had been using a dual STC-1000 connected to a chest freezer for cold; a reptile bulb in a can for heat. The system worked great, but I'm curious to see if I can just use ambient temperature in my garage and a heat source to achieve the same end.

Check out all the keezer builds on the DIY section. Rigging a STC-1000 would be easy and inexpensive. I would also put another 5-10 gallons of water in there as thermal mass to keep the internal temp of the freezer even more stable.

Put an ice bucket in when ferment first starts to combat rise in temp. It will work fine but you may have to tinker a bit. I lager like this all the time with old coolers and ice. It is so simple I don't see spending money o anything fancy or automated.