Reuse Cabinet "Son-of-a-Fermenter"

[Holgar]

Hey Everyone,
Wanted to post quickly about my fermentation cabinet built last weekend - it works really well... a bit too well (will explain that later).

Notes on chamber set up.
Cooling
o 11”x6”x23” Ice Pack holding chamber
o 2 x 120mm fans for pulling air in one end (from fermentation chamber) and pushing out the other end (into chamber)
o Fully insulated and foil taped
o Bottom lined with ‘marker board’ to increase durability of the foam
o Front wood panel is missing (with weather stripping to fill gaps)
Heating
o Lasko My Heat 200W
o Mounted with L brackets from the top of the chamber
Temp Control – STC-1000
Chamber
o 14.5”x28”x23” (two carboys)
o Fully insulated and foil taped
o Bottom lined with ‘marker board’ to increase durability of the foam
Insolation
o 1” insolation (I think it’s this type)
o Foil tape all seams, holes, etc.
o Weather stripping around doors

The heater works too well... I pitched the cider a little too cool and triggers the temp controller to run the heater. The chamber is so air tight that the air inside gets super hot (while the temp probe is reading cooler in the fermenter). The space heater thinks something is wrong and shuts down and will only be reset if it's turned off for 10 minutes!

So the problem is solved by measuring the air temp, not the liquid temp of the cider. A huge bummer - any idea how to mitigate this? I need the heating circuit to not allow the air temp to exceed a certain point.

 

[pricelessbrewing]

Hey Everyone,
Wanted to post quickly about my fermentation cabinet built last weekend - it works really well... a bit too well (will explain that later).

Notes on chamber set up.
Cooling
o 11”x6”x23” Ice Pack holding chamber
o 2 x 120mm fans for pulling air in one end (from fermentation chamber) and pushing out the other end (into chamber)
o Fully insulated and foil taped
o Bottom lined with ‘marker board’ to increase durability of the foam
o Front wood panel is missing (with weather stripping to fill gaps)
Heating
o Lasko My Heat 200W
o Mounted with L brackets from the top of the chamber
Temp Control – STC-1000
Chamber
o 14.5”x28”x23” (two carboys)
o Fully insulated and foil taped
o Bottom lined with ‘marker board’ to increase durability of the foam
Insolation
o 1” insolation (I think it’s this type)
o Foil tape all seams, holes, etc.
o Weather stripping around doors

The heater works too well... I pitched the cider a little too cool and triggers the temp controller to run the heater. The chamber is so air tight that the air inside gets super hot (while the temp probe is reading cooler in the fermenter). The space heater thinks something is wrong and shuts down and will only be reset if it's turned off for 10 minutes!

So the problem is solved by measuring the air temp, not the liquid temp of the cider. A huge bummer - any idea how to mitigate this? I need the heating circuit to not allow the air temp to exceed a certain point.

You should be able to fix this one of two ways.

one get a less effective heater, swap it out for some light bulbs or a reptile heater or something maybe? That should make it so when the stc says to turn it on, it won't be such a dramatic change and the ambient temp won't exceed the cider temp by too much.

Second, make a custom temp controller with a rasp. pi or arduino and the necessary switches and temp probes. You'll need two, one for the ambient and one for the cider temp. If cider temp is less than target temp, trigger ambient temp On until ambient temp exceeds (target temp + threshold). Should be simple enough to write and wire up if you're comfortable with that sort of thing. However, I'd recommend switching up the heat source. Might take couple tries to find one that's strong enough to affect the ambient temp enough for your temp range but weak enough to not heat ambient temp too quickly.

 

[FatDragon]

You should be able to fix this one of two ways.

one get a less effective heater, swap it out for some light bulbs or a reptile heater or something maybe? That should make it so when the stc says to turn it on, it won't be such a dramatic change and the ambient temp won't exceed the cider temp by too much.

Second, make a custom temp controller with a rasp. pi or arduino and the necessary switches and temp probes. You'll need two, one for the ambient and one for the cider temp. If cider temp is less than target temp, trigger ambient temp On until ambient temp exceeds (target temp + threshold). Should be simple enough to write and wire up if you're comfortable with that sort of thing. However, I'd recommend switching up the heat source. Might take couple tries to find one that's strong enough to affect the ambient temp enough for your temp range but weak enough to not heat ambient temp too quickly.

Another vote for the first suggestion - I wrote up a response but forgot to hit post, and my recommendation was swapping the heater for a 25-50W reptile heater, an electric blanket, or an electric heating pad. Also, don't insulate the probe from the air too well, or you could get a lot of inefficient temperature swings rather than keeping the temperature relatively even with an adjustment here or there like you want.

 

[pricelessbrewing]

Another vote for the first suggestion - I wrote up a response but forgot to hit post, and my recommendation was swapping the heater for a 25-50W reptile heater, an electric blanket, or an electric heating pad. Also, don't insulate the probe from the air too well, or you could get a lot of inefficient temperature swings rather than keeping the temperature relatively even with an adjustment here or there like you want.

Yeah 200w ceramic space heater seems like a lot of overkill, but I've never made a heated ferm chamber. I'd just buy a bunch of options, try them all out and see which I liked most.

 

[Holgar]

Yea... I'm realizing the overpowering nature of the heater. It was such a good deal! Dreading ripping the wiring out for the heater, I think i'm just going to cut the cord and use it to splice in a lightbulb + small 5v fan to recirculate the air. That way I don't have undo the insulation.

 

[FatDragon]

Yea... I'm realizing the overpowering nature of the heater. It was such a good deal! Dreading ripping the wiring out for the heater, I think i'm just going to cut the cord and use it to splice in a lightbulb + small 5v fan to recirculate the air. That way I don't have undo the insulation.

That should do ya. You can always put a new plug head on the space heater's cord and use it as normal (being certain to seal it off well, of course). Afraid Walmart probably won't accept the Franken-heater as a return, though...