Fermentation fridge heating for 2 fermenters

[NeoY2k]

Hello,
I will be using a fridge this winter as a fermentation chamber for fermenting ales.

I will be putting two 30l fermenters (buckets) in it.

I am wondering what to use as a heating element and where to put it.

1) I could use a reptile heater at the bottom to heat the air in the fridge.

2) I could use a seedling heating mat. I could put one in the bottom of the fridge as a heat source and benefit? from a lower temperature and wider radiating surface vs the reptile heater.

I read here some people add water bottles on top of them for added thermal mass. How much would you recommend adding a small fan?

Which power would you go for a 200x50x50 cm fridge? I have a choice of 21w or 30w. I could put a couple of them if needed. Temperature in my garage can drop to about 0 degree Celsius.

Would you put the temps sensor on one fermenter and estimate the other one should be around the same, or stick it in a water bottle between them?

3) I could use two seedling heating mats, one stuck on each fermenter. But I will have only one temperature regulator (one fridge) and one temp sensor, so I am not sure this is a good idea. The mats may not heat precisely the same amount, on top of the individual temperature variations.

4) Other solutions? Heating tubes are harder to obtain and more expensive.

Also, this fridge will go back to normal fridge duty in the summer, so I will not drill holes in it (I have a smaller one I can drill but that can only take 1 fermenter). I am thinking of just running the wires between the door and the fridge. The door has a locking mechanism. In your experience does this damage the seal? I get it will not seal as well as if the wires weren’t there but I don’t feel too worried about it. I might be wrong.

Thank you,
Nicolas

 

[AlexKay]

I’ve been really happy with what I’ve settled on after a few iterations:

A fan
A silicone heat pad (used for engine block heating), attached to
A small aluminum plate

I particularly recommend using waterproof electronics for this kind of application.

I leave the fan on all the time, and just lean the plate with the heater behind it so that when it goes on, warm air circulates fairly quickly.

 

[day_trippr]

fwiw, I use 40 watt ceramic heat emitters (aka reptile bulbs) in my ferm fridges with 12VDC pc fans. The fans run continuously while the bulbs are controlled by BrewPi controllers. This is representative of the setups for my three fridges...

I run power for the fans and heater and temp sensors lines along with a CO2 line all through the back wall on each of three full-size top-freezer fridges at the top left corner of the food chamber. For some unfathomable reason I still have all the removable plastic and glass "guts" and could restore each of them as "fridge/freezers" in short order...

Cheers!

 

[NeoY2k]

Thank you.

Where do you stick the temperature probe?
Thank you,
Nicolas

 

[AZ Maverick]

I have two re-purposed 75 bottle wine refrigerators that I now use as beer fermentation chambers.
I went the cheap simple route.
I use an Inkbird ITC-308 external temp controller to control the fridge cooling and for heat I simply tossed in a cheap $12 hair dryer....
Simple and cheap - but it works.
I attach the temp probe to either my ferm bucket or to the wall of the fridge depending on how hard I want the compressor to work (usually I leave it wall of the fridge.

 

[day_trippr]

Where do you stick the temperature probe?

I pin the "beer" temperature sensors under a thick foam pad using a velcro strap...

Cheers!

 

[Mark3885]

I like your blow off tube hold down device, I don’t use glass carboys often, only for small batch experiments.

 

[NeoY2k]

Great thank you all!
Nicolas

 

[quantumguy]

I have two seeding mats attached to the opposite walls of my fermentation fridge (using 2-sided velcro). Both are attached to an extension cord, which is then attached to an Inkbird. I also have a small computer fan that runs continuously.

 

[seatazzz]

I just use a simple heat lamp (the kind with a clamp) set where it can't melt anything. Takes a bit longer to get the temperature where I need it, but since I don't use my ferment fridge for kveiks (those just go in the house) it rarely turns on unless it gets super cold in the garage. Controller is a bayite I got from Amazon a few years ago, works great. The heat lamp seems to do a better job of getting all the wort to the temperature I need. I used a mat for a while, but got concerned that the bottom wort was getting warmer than the rest of it.

 

[wsmith1625]

I like the gentle heating from my Fermwrap. You can make your own much cheaper if you buy the Flexwatt by the foot and make it yourself. I use bungee cords to attach to my fermenter so I can remove it easily.

 

[redrocker652002]

I have two re-purposed 75 bottle wine refrigerators that I now use as beer fermentation chambers.
I went the cheap simple route.
I use an Inkbird ITC-308 external temp controller to control the fridge cooling and for heat I simply tossed in a cheap $12 hair dryer....
Simple and cheap - but it works.
I attach the temp probe to either my ferm bucket or to the wall of the fridge depending on how hard I want the compressor to work (usually I leave it wall of the fridge.
View attachment 869306

Hairdryer is a really interesting idea. I never thought of that. Cheap, easy and would heat things up pretty quick I would guess.

 

[day_trippr]

Using a hair dryer burning hundreds of watts of juice as a ferm chamber heater could easily be the biggest case of overkill-kill-kill ever!
I use a single 40w ceramic bulb in each of my three 18 to 22 CF fridges and that's plenty of heat...

Cheers!

 

[govner1]

Using a hair dryer burning hundreds of watts of juice as a ferm chamber heater could easily be the biggest case of overkill-kill-kill ever!
I use a single 40w ceramic bulb in each of my three 18 to 22 CF fridges and that's plenty of heat...

Cheers!

This! I’ve used a ceramic bulb for years after a small hairdryer caused a fire in my first ferm chamber. Fortunately, my temp controller cut the power and damage was limited to just the interior!
The ceramic bulb also eliminates light strike.

 

[NeoY2k]

Well I am trying a 30w seeding heating mat in a >400l upright fridge.

If the fridge is already at target temp, It is barely able to prevent the temperature dropping in the night. One might consider that it works though, but if temperature drops it might probably not be able to keep up.

It is however unable to raise the temp even 1 degree Celsius after a couple hours despite a fan circulating the heat.

Outside (basement) temp between 6-13 Celsius.

I put a 1800w space heater, it ramped it up to temp in less than an hour, but the temperature was not very uniform, and it overshot. Might need a second fan to circulate the air.

Then I switched to the heating mat to maintain temperature.

I ordered a small heating fan akin to your laskos.

 

[AZ Maverick]

Using a hair dryer burning hundreds of watts of juice as a ferm chamber heater could easily be the biggest case of overkill-kill-kill ever!
I use a single 40w ceramic bulb in each of my three 18 to 22 CF fridges and that's plenty of heat...

Cheers!

The hair dryer set on low uses 470 watts of electricity.
It usually only runs for a couple of minutes (if that) to achieve target temp.
It's VERY cheap to run, the refrigeration costs WAY more.

 

[day_trippr]

And I bet it overshoots the controls like crazy.

 

[AZ Maverick]

And I bet it overshoots the controls like crazy. Y

Nope, I've been using it for years and it works perfectly.
Here is a Tilt report from one of my lager brews.
Yep, it's just a hair dryer and the Inkbird controller....