Putting together a temperature controlled fridge

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Leard
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Putting together a temperature controlled fridge

Post by Leard » Fri May 04, 2018 10:02 am

I've gotten hold a cheap fridge that I'm going to use to control the temperature of my fermentation, before I've been relying on keeping my bathroom cool and I think it's been holding back how good my beers turn out.

I picked up one of the Inkbird temp controllers that I'll hook up to the fridge. The fridge is in a particularly warm room anyway and it's warm outside so I'm just concerned with keeping the temperature down. I'll probably invest in a heater belt or something when winter rolls round.

What do I do with the actual temperature probe? Should I keep it in a glass of water or would it be better attaching it to the outside of the plastic bucket fermenter? And should I set the probe to the exact temperature I want to reach, or should I aim for a figure lower or higher?

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Re: Putting together a temperature controlled fridge

Post by monkeyboy » Sat May 19, 2018 10:24 pm

I attach the probe to the side of the fermenter, about half way up. Over the top of the probe I tape some bubble-wrap, the idea being to make sure that the probe is reading the temperature of the FV, not the air temp. In tests, the probe temp was about .3 of a degree off from the wort temperature when I checked it with my (very accurate) thermometer. 0.3 is near enough in my opinion, so I just set the temp of the inkbird to be the temperate I want, I don't adjust.
Since getting my brewfridge set up, my beers have noticeably improved. I hope you get the same positive outcome.
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Manngold
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Re: Putting together a temperature controlled fridge

Post by Manngold » Sat May 19, 2018 10:27 pm

Same as above. Just tape it to the side of the FV. I would invest in a tube heater and a small pc fan. That was you can ensure temp is maintained . My tube heater was something like £10 from eBay. And I just asked the it department at work for a couple of fans from old computers.

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IPA
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Re: Putting together a temperature controlled fridge

Post by IPA » Sun May 20, 2018 8:25 am

The best idea is to buy a stainless steel thermowell and install it in your fermenting vessel. That way the sensor is where it ought to be in the middle of the fermenting wort.
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vacant
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Re: Putting together a temperature controlled fridge

Post by vacant » Sun May 20, 2018 8:25 am

Manngold wrote:
Sat May 19, 2018 10:27 pm
I just asked the it department at work for a couple of fans from old computers.
240V fans? I power my stir plate computer fan with an old phone charger.
I brew therefore I ... I .... forget

Manngold
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Re: Putting together a temperature controlled fridge

Post by Manngold » Sun May 20, 2018 1:59 pm

vacant wrote:
Sun May 20, 2018 8:25 am
Manngold wrote:
Sat May 19, 2018 10:27 pm
I just asked the it department at work for a couple of fans from old computers.
240V fans? I power my stir plate computer fan with an old phone charger.
In all honesty I have no idea. I had just seen YouTube videos of people using them so asked the it department. They weren’t really that bothered at letting me have some.

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Re: Putting together a temperature controlled fridge

Post by McMullan » Sun May 20, 2018 3:04 pm

What IPA typed.

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jmc
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Re: Putting together a temperature controlled fridge

Post by jmc » Mon May 28, 2018 1:54 am

Thermoelectric probably ideal but I've got mine held against side of fv using camping mat taped to fv. It's worked well for years now.

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7593steve
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Re: Putting together a temperature controlled fridge

Post by 7593steve » Tue May 29, 2018 9:23 pm

You'll probably need a heater to maintain a steady temperature, just chilling will overshoot and go too cold. I also tape my probe to the side of the FV. The computer fans will be 10 or 12 volt even out of an old desktop, as has been said already they run on an old charger, just cut the connector off and join the wires.

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spook100
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Re: Putting together a temperature controlled fridge

Post by spook100 » Wed May 30, 2018 10:59 am

On my system I have found that taping the probe to the side of the FV with *too much* insulation over the top causes overshoot problems. Because the liquid in the FV has a much greater thermal capacity than the air in the chamber it takes longer to heat up. If you wanted to raise the temperature of your liquid by say 2C then your heater is going to kick in and keep heating until the liquid temp has got to the new level, by which time the air in the chamber might be up to 50C. The heater will then turn off but the FV is surrounded by really hot air and the temp continues to rise until the cooler kicks in - and then you have the same problem in the opposite direction. This results in wild fluctuations that your system and your yeast will have to deal with.

I find that taping the probe to the FV with a thin layer of insulation (bubble wrap, 5mm foam) works best because it gives the probe a some temperature feedback from chamber itself. Doing it this way your heating or cooling will cycle on and off every few minutes until the target temperature is reached without overshooting.

You should also remember that the only time that you really need to worry about the difference between air and liquid temperature is during active fermentation because it is exothermic and can heat the temperature of the wort to significantly more that that of the air. The rest of the time the liquid and air temperatures should equalise through normal heat exchange and you can just leave the probe hanging loose in the chamber.

I use one of these desktop heater for my heating. They take up very little space and have a fan built in to circulate the air. They also run directly off 240v so no transformers required.
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rowettbrew
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Re: Putting together a temperature controlled fridge

Post by rowettbrew » Sun Jun 03, 2018 12:50 pm

I think the most important thing here (and I've worried about this topic in the past) is that you choose one method and stick to it - that way your measurements over time will be consistent - precision being more important than accuracy.

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