Chest freezer for fermentation questions

[Jtk78]

I think I'm about to bite the bullet and buy a used chest freezer to build a fermentation chamber. The one I'm looking at is a 9cuft Whirlpool, and the pics makes it look as if it doesn't have a hump, so I'm hoping I won't have to build a collar. I plan on buying an Inkbird 308. I already have another temp controller, but it only does heating OR cooling.

So if I bought 2 fermenters wraps, I could potentially have 2 carboys at different temps, correct?

Would this set up be correct? Carboy A I want at 62F. Carboy B I want at 68. Carboy A would get the Inkbird temp probe taped to it and a fermwrap plugged in to the Inkbird along with the freezer. I would assume set the Inkbird up to 61.5 - 62.5F.

Carboy B would get my current temp controller probe taped to it with its fermwrap plugged in and the controller set to 67.5 - 68.5F. I know the freezer is going to keep ambient about 62, but I'm hoping the fermwrap on this can overcome that.

Also;
- Do I need to have a small fan running in there to keep the air moving and a consistent temp?

- Should I line the bottom with anything to prevent the bottom of the carboys from getting real cold, or cut out a round piece of carpeting or rubber just large enough for the carboys to sit on?

- Lastly, are most of you taping or strapping the probes to the carboys with some insulation over them, or going with the thermowells? I have Fermonsters, and I think I'd need to buy new lids if I went with the latter. I'm pretty sure I've seen them, but don't really need any extra expense right now either.

Thank you much for your help.

 

[b-boy]

Yes on a fan.

I have a rubber mat on the floor of my chamber. It has 'waffle' cutouts, so it keeps the carboys off the floor, but still lets air pass through. I use it mostly to avoid denting the floor when I use kegs. I've never had trouble with temp variations. That's probably because of the fans.

I recommend a thermowell. It allows you to get pretty accurate readings of wort temperatures.

My ferm chamber has dual controllers. One controls the freezer and a heat source. The other I can use as an alternative heat source. I have a piece of 2" foam board that I can slide in. I use this to create warm/cold sides of the freezer. I use a small heating pad in the warmer side to bump the temp a few degrees. The colder side runs as usual. It works fairly well.

 

[Morrey]

I don't see why your two temp plan wouldn't work. Say you set your cooling to be at 62F, and I'd believe the fermwrap on the other fermenter will push that individual temp up just fine. Its kind of a push/pull situation, but the temps are so close I think that should work fine.

I tape my Inkbird probe to the fermenter side with blue painter tape. Then I cover that layer with a neoprene beer coozie held on by another strip of blue tape. The fermwrap does not completely encircle the typical fermenter, so I place my probe centered in the open area the fermwrap doesn't cover. I have pretty much shifted to thermowells which are easier to handle.

I use a small AC computer fan just to keep air currents moving. But in your case with direct heat from the fermwrap, I wouldn't think it completely necessary. Cool surrounds the freezer by coils so no real issue there either. I just put my fermenters into the freezer never using carpet or such other insulators, but you'll se a lot of variations and ingenuity in this area to personalize the way folks set this up.

 

[Jim311]

I would think you'd actually not want to circulate air personally, since one is being heated and the other cooled. In fact it might even be nice to make up a divider in there out of foam insulation.

 

[patthebrewer]

I think your plan might work. I feel as though ferm wrap will heat up the whole space a little, causing the freezer to kick on more.....which in turn will cause the ferm wrap to heat up more. It will be a fight between the two. Having said that I have never tried this setup before so, mine is just an educated guess Really there is no way to really know until you try it. My suggestion is to do several dry runs using plain water in your fermenters. Water is not going to generate the heat that fermenting wort will, but it should give you a pretty good idea whether your setup will work.

 

[Jtk78]

Thanks for the replies. Sounds like I'm at least starting the race from the right spot. I will probably start without the thermowells and set them up later. I think I'll put something on the floor, just have to figure out what once I get it. I also think I'll try the pre-run with water. Can't wait to get it set up and fine tuned.

 

[Hwk-I-St8]

Yes on a fan.

I have a rubber mat on the floor of my chamber. It has 'waffle' cutouts, so it keeps the carboys off the floor, but still lets air pass through. I use it mostly to avoid denting the floor when I use kegs. I've never had trouble with temp variations. That's probably because of the fans.

I recommend a thermowell. It allows you to get pretty accurate readings of wort temperatures.

My ferm chamber has dual controllers. One controls the freezer and a heat source. The other I can use as an alternative heat source. I have a piece of 2" foam board that I can slide in. I use this to create warm/cold sides of the freezer. I use a small heating pad in the warmer side to bump the temp a few degrees. The colder side runs as usual. It works fairly well.

Why yes on the fan? I run an inkbird chest freezer ferm chamber and I've never used a fan. I use a thermowell and it seems to hold temp extremely well.

 

[Morrey]

I think your plan might work. I feel as though ferm wrap will heat up the whole space a little, causing the freezer to kick on more.....which in turn will cause the ferm wrap to heat up more. It will be a fight between the two. Having said that I have never tried this setup before so, mine is just an educated guess Really there is no way to really know until you try it. My suggestion is to do several dry runs using plain water in your fermenters. Water is not going to generate the heat that fermenting wort will, but it should give you a pretty good idea whether your setup will work.

Your suggestion to try a test run with water only is a very wise suggestion indeed! I was setting up an FTSs cooling system using a cooler with an ice bath and frozen water bottles as a cooling medium. I tested with water and found lots of things/issues to deal with, but better with water instead of a fermenter full of valuable wort.

 

[Morrey]

Why yes on the fan? I run an inkbird chest freezer ferm chamber and I've never used a fan. I use a thermowell and it seems to hold temp extremely well.

I think it all depends on the heat source in a freezer. For example I often use a ceramic reptile bulb when temps dip low in the winter. I'll use a computer fan to gently circulate the heat generated by that ceramic bulb.

In the case of using a fermwrap or heat belt in direct contact with a fermenter, I don't see that a fan would be of much value.

Like you, I have shifted almost 100% over to thermowell's. Although I use conicals ported specially for thermowell's, there are dual ported caps available for carboys that can handle both a thermowell and an airlock or BO tube. Thermowells are very effective IMHO.

 

[Hwk-I-St8]

I think it all depends on the heat source in a freezer. For example I often use a ceramic reptile bulb when temps dip low in the winter. I'll use a computer fan to gently circulate the heat generated by that ceramic bulb.

In the case of using a fermwrap or heat belt in direct contact with a fermenter, I don't see that a fan would be of much value.

Like you, I have shifted almost 100% over to thermowell's. Although I use conicals ported specially for thermowell's, there are dual ported caps available for carboys that can handle both a thermowell and an airlock or BO tube. Thermowells are very effective IMHO.

The engineer in my likes the thermowell solution. I have one where the actual thermowell is built into the plug that also has a hole for the airlock. So far I've been running a neutered 3 piece airlock to a hose for my blow off tube, but I'll probably get a two port lid for the big mouth bubbler and use a much bigger blow off tube for the huge RIS I plan to brew in July.

 

[Morrey]

The engineer in my likes the thermowell solution. I have one where the actual thermowell is built into the plug that also has a hole for the airlock. So far I've been running a neutered 3 piece airlock to a hose for my blow off tube, but I'll probably get a two port lid for the big mouth bubbler and use a much bigger blow off tube for the huge RIS I plan to brew in July.

Good idea, that center shaft is idea for a 1/2" silicone BO hose.

Not sure if those point and shoot infrared thermometers are super accurate, but I tried something that sold me on the thermowell. It was last winter and I had a plastic fermenter pail in my hall closet bubbling away at ambient of 67F. Since I had the lid drilled for a thermowell, I slid the thermowell in place to plug the open hole. Had a BO tube going from the other vent grommet. This was at high krausen so I plugged in my Inkbird and slid the probe in place and let it sit a bit to stabilize. I then took a reading on the outside of the pail with the IR thermometer. I was surprised the outside was 4 degrees cooler than the thermowell/Inkbird read. I realize there may be some accuracy error between these devices, but I firmly believe we get the best and most accurate readings from the thermowell in the center of the liquid.

 

[Jtk78]

https://www.theweekendbrewer.com/products/homebrew-thermowell-with-stopper?variant=36279044931

This site sells thermowells with a number 10 stopper which will fit in the Fermonster lid. I think this is the route I'll go.

I've also used the center post of a airlock for a blowoff with very good success.

 

[b-boy]

Why yes on the fan? I run an inkbird chest freezer ferm chamber and I've never used a fan. I use a thermowell and it seems to hold temp extremely well.

I use a fan to prevent temperature stratification in the chest freezer. I have one in my keezer as well. I point it at my ceramic reptile heater bulb to dissipate the heat.

 

[Hwk-I-St8]

I use a fan to prevent temperature stratification in the chest freezer. I have one in my keezer as well. I point it at my ceramic reptile heater bulb to dissipate the heat.

Ah....I use a heat belt, so there's no need to ensure the heater output is the same throughout the unit.

 

[BubbaMan]

Tagged for education.

 

[Jtk78]

I did purchase the freezer and will be picking it up on Saturday. I have already ordered my inkbird. I won't need this up and running this weekend, but before I brew again in a few weeks.

The bottom does not have a bump or high side , but will still require a collar due to the height of the inside and my fermonsters. No biggie. I think I will build it out of 2x8 with weather stripping above and below. This will be better planned after I have it.

I've decided I am going to go with a small fan to keep the air moving, as well as an Eva renewable dehumidifier on the opposite side. I've researched a bit and heard of a lot of moisture and even mold.

I've also read of some concerns with over shooting temps when using the thermowell, i.e. driving ambient down to 50 when trying to lower wort temp a couple degrees. Anyone in this post experience this? My guess is once things stabilize, if you keep changes small, it shouldn't be much of an issue. I have an indoor/outdoor thermometer and will hang the outdoor sensor in there to monitor.

Is there anything else you would recommend when building this thing? Once I have it in place, it's not going to be the easiest to move out to make modifications.

Thanks again.

 

[Hwk-I-St8]

I did purchase the freezer and will be picking it up on Saturday. I have already ordered my inkbird. I won't need this up and running this weekend, but before I brew again in a few weeks.

The bottom does not have a bump or high side , but will still require a collar due to the height of the inside and my fermonsters. No biggie. I think I will build it out of 2x8 with weather stripping above and below. This will be better planned after I have it.

I've decided I am going to go with a small fan to keep the air moving, as well as an Eva renewable dehumidifier on the opposite side. I've researched a bit and heard of a lot of moisture and even mold.

I've also read of some concerns with over shooting temps when using the thermowell, i.e. driving ambient down to 50 when trying to lower wort temp a couple degrees. Anyone in this post experience this? My guess is once things stabilize, if you keep changes small, it shouldn't be much of an issue. I have an indoor/outdoor thermometer and will hang the outdoor sensor in there to monitor.

Is there anything else you would recommend when building this thing? Once I have it in place, it's not going to be the easiest to move out to make modifications.

Thanks again.

I don't worry about the ambient temp, just the temp of the liquid that's fermenting. The thermowell does that extremely well. I also have a heat belt to ensure that it doesn't get too cool. I cold crash in mine and was worried about overshooting the temp. I set it at 39 initially and I think the wort dropped to about 37.5.

I chill my wort to the ferm temp before racking to fermenter. That way the wort is already at the correct temp and the Inkbird only needs to maintain it. I usually wait about 30 minutes after putting the probe in the inkwell before powering on the inkbird.

When raising my ferm temp for a diacetyl rest, I raise it a degree each morning and evening.

When building your collar, be careful removing the hinges. They're sprig loaded and more than one person has gotten whacked by them as the screws give way.

 

[Jtk78]

Thanks Hawks. I've read about the hinges too, but thanks for the reminder. Saw a picture of a nail holding one down. Not sure yet if that will work, but I'll see.