Heat exchanger

[Minbari]

Anyone see any reason I couldnt use coiled copper tubing as a heat exchanger IN the fermentor? This would circulate cooled water/glycol to control Ferm temp.

It would get cleaned and sanitized at the same time the bucket does, of course.

 

[jtp137]

Most people use stainless for this easy to clean. Dont see why you couldnt use copper


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[Minbari]

Only reason for copper is it is cheap and easy to bend.

 

[jtp137]

Take a look at this place for some SS coils

http://www.stainlessbrewing.com


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[WhamFish]

So I'm not a metal chemist, but I know from working in aquariums that copper always leaches into the water at some rate (enough to kill some animals in aquariums even if the water is just passed threw copper fittings). So I would guess that copper is going to slowly leach into the beer, the low pH of the wort cant help. I understand the amount that leaches from a copper chiller during the 10-40min wort chill is good because it is used as a co-enzyme for the yeast, but the amount that leaches over a full ferment is probably going to be above the amount the yeast will use.

I'll defer to someone else that maybe has some first hand experience or knows more.

Are you attempting to control fermentation temp? Maybe I can suggest another method, there are strong advantages to non-direct cooling methods. I've just recently built a fermentation control system, I decided against direct temperature control.

 

[Minbari]

ok, lets try this again. did HBT get hacked?

It is for fermentor temp control. I dont have room (or desire) for another fridge as a ferm chamber, but I have a small freezer that I can use a water/glycol mixture to cool with. a HE coil seemed the simplest method to use.

I am also looking at the cool zone jacket for external cooling. Same method for moving the coolant.

This is all in the design phase right now, so suggestions are welcomed.

 

[WhamFish]

So when I considered this I thought about using a stainless coil that would go in and out through one of those orange carboy hoods. You'll also need a thermowell for a temp probe and room for the blow off tube. Thats a bunch of stuff, thats not ultimately why i decided against it but something to consider.

Alternatively, you could place the carboy in a bucket or cooler (they fit well inside the orange rubbermaid water coolers) then fill with water and regulate the temp of the water with a copper coil. If the cost of the rubbermaid is a concern you can make one with two different small trash cans placing the smaller one inside the bigger one then filling the space with Great Stuff foam.

Similarly, the 4 cubic foot dorm fridge works too but you already said your not interested in this method.

So the down side i guess here is that both indirect methods require extra room, which seems to be at a premium in your case. The up side is that they are much more temperature stable.

 

[porterpounder]

I have the same concerns on a design I'm doing for a small open fermenter. I've decided to go with the copper coil outside of the fermenter and insulating the whole thing with Reflectix.

 

[Minbari]

So when I considered this I thought about using a stainless coil that would go in and out through one of those orange carboy hoods. You'll also need a thermowell for a temp probe and room for the blow off tube. Thats a bunch of stuff, thats not ultimately why i decided against it but something to consider.

it will be in a ferm bucket to start with, maybe a wide mouth bubble style. room should be ok with either type. I do plan on making a thermowell for the setup

Alternatively, you could place the carboy in a bucket or cooler (they fit well inside the orange rubbermaid water coolers) then fill with water and regulate the temp of the water with a copper coil. If the cost of the rubbermaid is a concern you can make one with two different small trash cans placing the smaller one inside the bigger one then filling the space with Great Stuff foam.

Love this idea! the water in the cooler/larger bucket/small garbage can would have great contact with the ferm bucket and not worry about copper contamination.

Similarly, the 4 cubic foot dorm fridge works too but you already said your not interested in this method.

So the down side i guess here is that both indirect methods require extra room, which seems to be at a premium in your case. The up side is that they are much more temperature stable.

that seems counter intuitive. you would think direct cooling would have a quicker effect in cooling. I dont see many people do it, which I why I started this thread.

 

[WhamFish]

"that seems counter intuitive. you would think direct cooling would have a quicker effect in cooling. I dont see many people do it, which I why I started this thread."

So you are totally correct, direct temp regulation is more efficient, but the indirect method allows the surrounding medium to vary its temp over a wider range then the PID algorithms is employed to achieve stable temps in the target.

Direct methods do change the temp faster but the PID algorithm tends to have a harder time optimizing for this and you end up with oscillations. Yes in theory you should be able to tune the PID but in practice I think the indirect method ends up with more stability. Since what is being heated or cooled is allowed to overshoot the target temp all of the oscillations end up occurring in the surrounding media while the amplitude and period of those oscillations are tuned by the PID to result in stability in the beer.

The added bonus is that the only new thing that goes into the beer is a thermowell.

 

[Minbari]

ya, I can see the challenge in programming that. would need a higher Derivative and pretty low Integral to keep it from ocs and still hit the target in a reasonable amount of time.

I do like the idea of not putting anything in the beer, too.

 

[Headley_Lamarr]

I don't have room for a permanent ferm fridge either. I've had success with this hybrid approach.

I have a larger ice cube cooler filled with a water bath. This has a homemade lid to accommodate the airlock/blowoff and 2 plastic tubes. In that cooler, I place my carboy, a thermowell (hooked up to a temp controller) taped to side of the carboy in the bath, and a tiny aquarium pump (powered by the temp controller) with tubing running out of the lid. I place a 5 gallon cooler next to it. In the 5 gallon cooler, I place my immersion chiller and fill the cooler with ice and water. One tube receives warmer water via the aquarium pump. The output tube sits in the large cooler and receives ice cold water to the water bath around the carboy. This works great and is pretty low maintenance. I put a couple ice pack in the 5 gallon cooler every evening. Though, it really doesn't need it that often as the cooler really keeps it cold.




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[Hermit]

Copper in the boil is a plus. Copper once fermentation starts is a NO. This is only from reading. I know people that get away using it in jockey boxes but that is pretty short term.

 

[Minbari]

Copper in the boil is a plus. Copper once fermentation starts is a NO. This is only from reading. I know people that get away using it in jockey boxes but that is pretty short term.

Ya, I have decided against an HE in the ferm chamber. I like the water bath idea with the HE in the bath instead.

 

[seph]

So I'm not a metal chemist, but I know from working in aquariums that copper always leaches into the water at some rate (enough to kill some animals in aquariums even if the water is just passed threw copper fittings).

Just an FYI, up until recently, copper was the standard for water pipes in residential and commercial buildings. Now plastic is way cheaper, and that's why it is used. Copper in the fermenter is another thing altogether, as has been covered by you and the OP. But I just wanted to mention that copper pipes are very common and they will not kill you.

 

[WhamFish]

Just an FYI, up until recently, copper was the standard for water pipes in residential and commercial buildings. Now plastic is way cheaper, and that's why it is used. Copper in the fermenter is another thing altogether, as has been covered by you and the OP. But I just wanted to mention that copper pipes are very common and they will not kill you.

Oh for sure, I didn't mean to imply that copper would kill you or anything like that. Just that marine life in aquariums tend to die if water is sourced from copper pipes and its untreated. For this reason I suspect that there is constant leaching of copper in water rather than eventual complete passivation. I just mean to reference this fact as the reason I suspect that there would be constant leaching and it would be detectable perhaps as a metallic off flavor in the beer.

I think we are all in agreement here though.

 

[Minbari]

Just an FYI, up until recently, copper was the standard for water pipes in residential and commercial buildings. Now plastic is way cheaper, and that's why it is used. Copper in the fermenter is another thing altogether, as has been covered by you and the OP. But I just wanted to mention that copper pipes are very common and they will not kill you.

as an addition to what Whamfish said, the copper pipe in your house doesnt get exposed to boiling temperatures or PH below 5 either.

dont know if that would have any contributory effects, but it might over time.

Ultimately, I think the temp control aspects of external regulation is what is the deciding factor here. could I alter my program so the PID could think quickly enough with it in the fermentor? sure, but why bother when external regulation will work with no changes.

 

[RmikeVT]

Glad you decided on water bath. I was about to say, "I think you are over thinking this, use a swamp cooler."

I use an igloo cube cooler filled with water that I put my better bottle into. I cycle a frozen 0.5L water bottles when I need to cool the bath. I did an experiment one time and measured the water bath temperature and measured the center column of wort temp in the fermentor and found that the the water bath only varied by 1* with the wort temp. This is of course after they reached equilibrium. Anyway - it works great. The cooler works phenomenally at keeping the temps stable. In the middle of summer my basement runs about 74-76ish degrees. I've managed to keep steam beers in the low 60's using this method. I am pretty sure if I used 1G soda bottles I could probably do a lager and keep in high 40's low 50's. I just haven't had the inclination to wait around 3 months for a lager.