55 gallon drum fermentation idea

I'd like to get some feedback from you guys about an idea...

I want to be able to ferment 1BBL batches in 55gal poly drums in my garage - with temperature control. I live in south louisiana, so I only need cooling. I have been giving it lots of thought, and currently have 2 options in mind.

1.) Build a big box in garage with wall studs, plywood, and insulation. Install window A/C unit that cycles with a regular johnson temp controller to keep the inside of the "box" at 60-something degrees. Put poly drums (more than 1) on casters to roll into and out of the room.

2.) Use a chest freezer to keep a reservoir of glycol soln at low temp. Pump glycol though a home-made jacket for each drum. The jacket basically be an insulating material that wraps around the outide, with a copper pipe running between it and the drum. The copper pipe would be formed to wrap back and forth around 1/2 of the drum and could be attached to the jacket itself. the idea being to be able to maybe "strap" the homemade cooling jacket to the drum, and a march pump would cycle on and pump glycol when needed.

The benefit to option 2, if done correctly, is the ability to crash cool. Dont think that would be feasible in idea #1.

Anyway, just wanted to bounce this off HBT. Thanks.

I would go for #2. I don't think a window ac would be anywhere near powerful enough to cool the 55 gal drums inside the garage especially when there are actively fermenting yeast heating them up. I'm no expert, just my $0.02. Sounds like quite the operation you'll be having! Keep us posted

Just googling some items and came up with option #3:

Drop stainless steel coil inside the fermenter drum to cool. Attach coil to lid, which is fed by the chest freezer/glycol pump chiller. Could easily wrap drum with something to insulate. I think this may be the most effective option at cooling.

I think Number 2 is the better choice given the size of the vessle and the thermal properties of plastic. During active fermentation the center of liquid in even a 5 gallon carboy is 3-4 degrees higher than ambient. 30+ gallons is going to be an even greater spread.

I think in either case you're going to find that cooling from the outside, through the plastic is going to be fairly inefficient. The plastic is going to have a tendancy to insulate. Have you considered placing the glycol cooling lined directly in the fermenter so its in direct contact with the liquid? I know that presents some sanitization difficulties, but it would be far more effective. If that's out of the question, I'd consider ways to increase the thermal connectivity between the wort and the cooling lines as much as possible. Possibly place the 55 gallon drum inside a larger drum, fill the void in between up with water and allow the glycol lines to be submerged in the outer layer of water to cool that, which then in turn would be exposed to the entire surface area of the outside of the fermenter. Water is approximately 7 times more efficient at heat transfer than air, so I think this might be a good idea, although I've never tried it. Regardless, the additional water would act to increase the overall thermal mass and help buffer against fluctuations in ambient temperature.

We are thinking about doing the same thing with some SS drums we aquired. One option to save on cost (and be able to wrap it many more time for the same cost) is to use PEX. Since you are using poly drums anyway, the thermal transfer isn't hindered anyway. With PEX, you could feasibly wrap the pipe tight (without spaces between loops) without getting into astronomical costs. You have to remember that wrapping a drum one time uses about 9 feet of pipe. If you want to wrap it 20+ times, well... you can seem where I'm going with this.

ajwillys said:

We are thinking about doing the same thing with some SS drums we aquired. One option to save on cost (and be able to wrap it many more time for the same cost) is to use PEX. Since you are using poly drums anyway, the thermal transfer isn't hindered anyway. With PEX, you could feasibly wrap the pipe tight (without spaces between loops) without getting into astronomical costs. You have to remember that wrapping a drum one time uses about 9 feet of pipe. If you want to wrap it 20+ times, well... you can seem where I'm going with this.

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Yeah, I wonder about the ability of a system like this (PEX or copper) and its ability to crash cool down below 40 deg. I think the PEX could keep it at a nice even temp. The coolant may need to circulate more, but I agree with you, it would work - if there were insulation around the whole thing. The cooling below that to drop yeast is what has me concerned.

I would also go for glycol, but with plastic there is going to be quite a bit more thermal resistance than with a typical stainless fermenter. Something like an immersion chiller in the drum itself might cool more effectively, but it may need to be fairly large to cool that much liquid at full fermentation.

If the glycol is really cold (around 20 degrees or so) and you have the drum completely wrapped in coils, I don't see how it could possibly not get cold. True, your thermal transfer properties are low with the poly/plastic and poor transfer rates, but its there continuously and completely. Of course, you would want to wrap in insulation afterwards. If you entire surroundings are 20 degrees, then the liquid should get cold pretty quickly, I would think. I mean, its not like we're cold crashing during active fermentation. No heat is being produced internally.

I wonder if you could wrap it in PEX or copper, clad it with some aluminum flashing, fill the gaps in the wrapping with a thermal gel of some sort that hardens, and then cover with insulation. This idea appeals to me very much and if I thought I could make something that would work for around $100 per drum, I would be willing to give it a try.

Pangea said:

Just googling some items and came up with option #3:

Drop stainless steel coil inside the fermenter drum to cool. Attach coil to lid, which is fed by the chest freezer/glycol pump chiller. Could easily wrap drum with something to insulate. I think this may be the most effective option at cooling.

Click to expand...

One of the guys in my club does this for his conical. I think he just uses water pumped through his kegerator though.