Freezer Fermenter with Flammable Refrigerant

[MAiton]

Hey guys,

I recently started a fermenter build using a 3.5 cubic foot freezer, a temperature controller and a ceramic reptile heater. As I got rolling, I noticed the warning label on the freezer indicates flammable refrigerant so I started doing some research. As it turns out, this stuff is dangerous at 60 degrees Celsius with a RH at about 50%. And according to my temp gun, the ceramic heater is above 100 degree Celsius. I'm just wondering what everyone else is using to bring the temperature up in their freezer builds. Heating blankets, belts, etc?

Mike

 

[mongoose33]

A heating mat is the usual way--you don't heat ambient, you heat the fermenter directly. Two popular methods are a reptile heating mat, or what's called "fermwrap."

You wrap it around the fermenter, secure it with bungee cords or wire or string or whatever, and it heats the fermenter directly. Since you want to maintain the temp of the fermenting beer, not ambient conditions, you put a temp probe against the fermenter and isolate it with a piece of insulation (foam, styrofoam, folded towels, whatever), or you put it down a thermowell.

I just bought a new freezer for my keezer, and it has the same warning on the side. It's primarily so that if you would puncture the system, what leaks out is flammable. If not punctured, should not ever be a problem.

 

[MAiton]

A heating mat is the usual way--you don't heat ambient, you heat the fermenter directly. Two popular methods are a reptile heating mat, or what's called "fermwrap."

With this setup, my temperature probe is 12" long and directly into the beer. Even though I am heating the air, I am basing my readings off the beer temperature itself. I made the mistake with a stout because my probe monitored the air instead and the beer. The fermentation was very fast and intense due to my yeast selection and I'm certain, hotter than it should have been.

But I think I will try a fermenter blanket. I put a temp gun on a heating pad that I use for sore muscles and it's at 35 degrees celsius.

 

[VVbrewery]

I've got a heating pad made to stick on the side of a ferment chamber that says on it not to place fermenter on it. It's very similar to a reptile heater but I've never checked how hot it gets. I use it in my freezer to heat the ambient air. The temp is monitored with a thermowell in the beer. The temp does yo-yo a bit if you change the temp radically but it always will because your not directly cooling/heating the wort like with a glycol system, but to hold a steady fermentation temp it works fine. It's never caused any problems and I always take the temp probe out of the beer to read the air temp instead if I'm cold crashing or making other drastic temp changes.