Chest freezer temperature variance

[ninjamonkey80]

So I tested my new chest freezer and set it for 55°. it will click on at 56° to cool down. it cooled down from 56° to 50°. so I figured I would split the difference to get the desired fermentation temperature and set it for 60° hopefully it will have a fermentation temperature of 57°. am I on the right track?

 

[JONNYROTTEN]

No...The freezer air temp works different than liquid temps. Liquid temp is slower to change and more stable. Set it for the temp you want or a little lower. Better yet get a 12" themowell for $12 and be done

 

[swampbrewcrew]

Are you measuring ambient temps, or are you putting the temp probe in a liquid? What offset do you have your controller set at?

Even if the offset is set at 1 degree, depending on the settings on your controller you may have a minimum run/rest time for your compressor. It will swing the ambient temperature by a good bit, but it would have little to no impact on a large volume of liquid.

 

[ninjamonkey80]

I'm measuring the ambient temp. The offset of set to one degree. what should I set the compressor delay to?

 

[ninjamonkey80]

My fermenter temp was already at 56 degrees I've had it in a refrigerator with temperature control for about a week but I just bought this freezer today

 

[schematix]

you need a thermowell in your fermenter and a small fan in the chest freezer. something like an eva-dry won't hurt either.

 

[doug293cz]

you need a thermowell in your fermenter and a small fan in the chest freezer. something like an eva-dry won't hurt either.

Or you can tape the controller temp probe to the side of the fermenter with some foam insulation covering the probe. Very popular method, that works great.

Brew on

 

[schematix]

Or you can tape the controller temp probe to the side of the fermenter with some foam insulation covering the probe. Very popular method, that works great.

Brew on

Didn't work great for me. Better than directly measuring ambient temperature but i found it to be a few degrees different than what the thermowell measured. The sensor was definitely influenced by the ambient air temperature. The compressor cycled much more frequently with the taped-on vs thermowell.

Also taping is a messy job. The only tape i found that sticks reliably also leaves residue that required solvents to remove.

So yah just like many things you can do it a bunch of ways, but the thermowell is the only way to get a really accurate and stable measurement of what's going on inside.

 

[owmatooth]

i popped a hole in the top of a two quart mason jar lid. stuck the probe in and filled it with water. Is a thermowell more advanced than that, or is that pretty much the idea?

 

[schematix]

i popped a hole in the top of a two quart mason jar lid. stuck the probe in and filled it with water. Is a thermowell more advanced than that, or is that pretty much the idea?

That method is probably the the least effective way to measure temperature i've come across. The temperature in the water jar doesn't represent the temperature of the fermenting wort. All that does is slow the rate at which the probe temp changes because the water acts as a buffer to the ambient air temp.

A thermowell is a hollow metal tube that goes into the fermenter so it's measuring the actual beer temperature in the center of the fermenter.

 

[JONNYROTTEN]

I'm measuring the ambient temp. The offset of set to one degree. what should I set the compressor delay to?

Set the compressor delay to the highest setting. I think its usually 10 deg. No wort temps will change in that time and its better for the freezer. You didn't mention what your using as a temp controller. The Inkbird 308 is what most use and work really well for around $35.

Aside from accuracy the themowell is SO much easier than taping/strapping and dealing with insulation every time. Just stick the temp probe in the themowell...that's it...simple simple

 

[RedlegEd]

That method is probably the the least effective way to measure temperature i've come across. The temperature in the water jar doesn't represent the temperature of the fermenting wort. All that does is slow the rate at which the probe temp changes because the water acts as a buffer to the ambient air temp.

A thermowell is a hollow metal tube that goes into the fermenter so it's measuring the actual beer temperature in the center of the fermenter.

+1 ^^^ this! You can get a 12" or 16" SS thermowell very inexpensively and insert your controller's probe into it. My recommendation, whether you use a bucket, large-mouth type fermenter, or carboy is to have the tip of the thermowell end up about 2-3 inches from the side of your FV. I've found this is the sweet spot to keep the temp swings down due to thermal momentum. Hope this helps. Ed


ETA: I'm assuming (yes, I know...) that you are using a controller of some type.

 

[owmatooth]

That method is probably the the least effective way to measure temperature i've come across. The temperature in the water jar doesn't represent the temperature of the fermenting wort. All that does is slow the rate at which the probe temp changes because the water acts as a buffer to the ambient air temp.

A thermowell is a hollow metal tube that goes into the fermenter so it's measuring the actual beer temperature in the center of the fermenter.

I get it. How do you account for several different fermenters in different stages of fermentation- or do you just prioritize the one that is in the active early phase?

just when I thought I was doing something right....


I'm heading to my lhbs in a few min to pick up this weekends grains, and i'll look for one. how does one get the tube into a glass carboy and also get an airlock on it? must be some sort of dohickey thingy for that. never seems to be an end to stuff to buy.

 

[schematix]

I get it. How do you account for several different fermenters in different stages of fermentation- or do you just prioritize the one that is in the active early phase?

Easy. I bought 2 chest freezers. Practically speaking though ale fermentations are DDFD in less than 6 days and lagers in 14 so I can't make as fast as it ferments. I keep 1 chest freezer now exclusively for cold storage of fermented and kegged beer.

I'm heading to my lhbs in a few min to pick up this weekends grains, and i'll look for one. how does one get the tube into a glass carboy and also get an airlock on it? must be some sort of dohickey thingy for that. never seems to be an end to stuff to buy.

https://www.midwestsupplies.com/carboy-cap-3-5-6-gallon-carboys

Thermowell in the center, blow off in the side. Airlocks are trash too...