Ghetto temperature controlled fermenter: would it work ?

[jfr1111]

Hi, I’ve recently started kegging and I my chest freezer is now used as a keezer. My « brewery » is a very small spare bedroom. We have another upright freezer in there for food and my girlfriend made it very clear she doesn’t want a third fridge/freezer in there. She also made a very angry face when I told her I would drag a big bucket in there again and fill it up with water to control my temperatures.

I’ve looked at other options, mainly commercially temperature controlled conicals and buckets, but they cost an arm and a leg. I also don’t want to buy and install an AC unit in there, which would be comically inefficient and stupid, what with the two large appliances cycling their compressor and bringing the temperature up.

I put my thinking cap on yesterday evening (which is rare nowadays) and devised a plan.

What I’m thinking of doing is buying a cheap 30 quart stainless stock pot off OBK and use an immersion chiller (stainless, since copper would probably leach at a low pH) and maintain temps with a digital controller and a pump to circulate ice water.

I already have all the tubing, the controller and the cooler to put the water. I could even use a regular plastic bucket.

I would drill the lid of the pot for the immersion chiller fittings, thermowell and an airlock.

Anybody tried something similar ? If so, what pump would be best ? I don't plan on lagering or cold crashing with the thing and would only control the bulk of primary ale fermentation. I plan on insulating the fermenter or maybe putting it inside an insulated box to reduce the amount of time the pump would have to cycle.

 

[christyle]

For it to work, you would need a temperature gradient between the two liquids (cooling water bucket and fermenter). You would have to have the bucket of water you are drawing from in the fridge or kept cold with ice through the day.

 

[jfr1111]

For it to work, you would need a temperature gradient between the two liquids (cooling water bucket and fermenter). You would have to have the bucket of water you are drawing from in the fridge or kept cold with ice through the day.

That's a given. I have an old 5 gallon cooler that I will use as a cold water tank. Since the setup will be in the same room as the freezer who is used to actually freeze food, I'll just put ice or ice packs every day to keep the water temperature as cold as possible.

Will 5 gallon be enough though, seeing as I will cycle back the water in the cooler when it has passed through the chiller ? I might have to run some tests to see how cold the cooler keeps the water once it is near freezing, to prevent the pump from having to cycle too much.

 

[christyle]

I didn't get it in your post, just making sure. I've never done it, so I'm not sure, testing with a beer would be the best way to find out, there's a lot of variables there...

In industrial refrigeration, they have something called a thermisiphon oil cooling system that occasionally get's used. It uses the natural convection of heating and cooling liquids to move the fluids without a pump. This may only work with the larger gradients they see, and I know requires a precise setup to get fluid to flow. In essence, a cool reservoir is at a point higher than the item to be cooled (your beer), and the cool fluid travels down into the heat exchanger. As it warms, density decreases and it gets pushed up to the reservoir by the denser, colder fluid coming down from the reservoir. This warm fluid cools in the reservoir before starting the cycle again. So.....a lot of work to avoid a small pump In refrigeration the cost savings can be large, which is why it came to be.

 

[noggins]

How big is your keezer freezer? If it's big nuf I've seen people split their keezer with insulation and use small heater connected to seperate temp controller to create a ferm chamber inside the keezer.

 

[johngaltsmotor]

If you're really considering this do it right and drill 2 holes in the side of the fridge for in and out cooling water lines, put a bucket in the fridge with water, run the water through your IC and back to the bucket and let the pump circulate the cooling water according to the controller thermocouple. Eventually you'll get sick of remembering to add ice and drain off the excess water from melting ice.

 

[jfr1111]

Keezer is very small, fits two kegs and maybe a third 3 gallon one. No way to fit a bucket.

The room where the setup is situated stays about at 66F to 70F. It's not so much that I can't keep the temperature down to correct levels, it's that I want to have complete control to the degree or so.

I'll run on test on the cooler to see how much temp I bleed per day, to insure that I don't have to fill the thing up with ice constantly. Using jugs of ice would insure there would be no need to drain the cooler.

 

[christyle]

The problem there is you wont be cycling warm water through it melting the ice off to pull heat from the cooling fluid. A cooler will hold ice in your house for a few days without issue if its a half decent cooler.

 

[jfr1111]

The problem there is you wont be cycling warm water through it melting the ice off to pull heat from the cooling fluid. A cooler will hold ice in your house for a few days without issue if its a half decent cooler.

Not sure I understand. The ice water will be in the cooler. That water will be circulated in the beer with the pump when the temperature control kicks in and the pump will shut off once the temperature is attained

 

[christyle]

It sounded like you were just going to put a cooler of ice water in the room and see how long it took to melt, I must have misunderstood.

 

[Bellybuster]

horribly inefficient design. The air conditioner would be more efficient. remember you have to make ice, that takes way more energy than cooling some air in a room thats already pretty much cool enough.
I would suggest limiting your yeast use to the room air temp or get another fridge.

 

[Bellybuster]

It sounded like you were just going to put a cooler of ice water in the room and see how long it took to melt, I must have misunderstood.

still sounds that way to me, am I mistaken as well?

 

[christyle]

horribly inefficient design. The air conditioner would be more efficient. remember you have to make ice, that takes way more energy than cooling some air in a room thats already pretty much cool enough.
I would suggest limiting your yeast use to the room air temp or get another fridge.

I disagree. In a fridge full of items, there is a lot of stored energy in there, adding a small amount more will take some energy, but not as much as you think. What type of air conditioner are you saying? Add an additional portable unit for this purpose, or lower his whole house temp to cool 5 gallons of beer?

 

[Bellybuster]

any energy taken from a freezer to freeze water has to be replaced or the temp will drop. A freezer is not an energy storage device.

Simply put, if you want 1 degree control over your fermentation, a cooler full of ice is not the way to go. Refrigeration is. The losses in such a system would be huge. You have a pump that generates heat, you have piping that loses energy etc etc etc. without active replacement of the energy used ..... anyway

food for thought.... you have a room at 66-70 degrees, a cheap fan is quite energy efficient and a towel is free from the closet. Evaporative cooling, probably tens of thousands of brewers making award winning beers doing it.

Son of Fermentation Chiller would be a better use of ice jugs than a quasi glycol system, there's another option.


forgive me if this is just something you want to do, I obviously missed that in the OP.

 

[jfr1111]

The biggest downside of evaporative cooling and other same methods is that they don't measure the temperature inside of the wort (ie. you must baby the thing constantly) and there's not much precision. I have done a LOT of beers that way, so I'm not knocking it, but I want more precision if at all possible.

From the feedback, I guess that recirculating ice water is not something that would work since it would not produce enough cooling power or need to much human intervention to work, which is probable true after thinking about it.

Rigging up an AC to cool a glycol/water solution could be an option as to have a bigger gradient in temperature ? That adds costs though.

 

[christyle]

any energy taken from a freezer to freeze water has to be replaced or the temp will drop. A freezer is not an energy storage device.

Simply put, if you want 1 degree control over your fermentation, a cooler full of ice is not the way to go. Refrigeration is. The losses in such a system would be huge. You have a pump that generates heat, you have piping that loses energy etc etc etc. without active replacement of the energy used ..... anyway

food for thought.... you have a room at 66-70 degrees, a cheap fan is quite energy efficient and a towel is free from the closet. Evaporative cooling, probably tens of thousands of brewers making award winning beers doing it.

Son of Fermentation Chiller would be a better use of ice jugs than a quasi glycol system, there's another option.


forgive me if this is just something you want to do, I obviously missed that in the OP.

Now you're saying something different. Using a fan and wet towel would easily be more efficient than an air conditioner or freezing water bottles. Never heard of the SOFC design, seems like a decent idea, especially for this application. Using refrigeration has PLENTY of losses in the system as well, it's not free energy.

A freezer is an energy storage device of sorts: A freezer full of frozen objects contains more potential energy than an empty one. If you have more items in the freezer, the temperature will not fluctuate as much, reducing cycle time of your equipment. Adding a water bottle will require some heat input that will need to be removed by the freezer, but it's minimal really, compared to lowering an entire house temperature or employing an additional air conditioner to lower the temps.

 

[christyle]

The biggest downside of evaporative cooling and other same methods is that they don't measure the temperature inside of the wort (ie. you must baby the thing constantly) and there's not much precision. I have done a LOT of beers that way, so I'm not knocking it, but I want more precision if at all possible.

From the feedback, I guess that recirculating ice water is not something that would work since it would not produce enough cooling power or need to much human intervention to work, which is probable true after thinking about it.

Rigging up an AC to cool a glycol/water solution could be an option as to have a bigger gradient in temperature ? That adds costs though.

Agreed on evaporative cooling, I made some simple attempts at it and gave up in favor of the chest freezer.

The ice bath recirculation will provide enough cooling for a small gradient, but will require constant tending. An ac glycol chiller will work, but will take up as much if not more room than a small chest freezer, be more complicated, prone to issue, and look much less "clean" unless hidden away somewhere.

I like the idea of the SOFC for your application. Minimal cost/complexity to get the job done. I've never used them but it makes sense to me how they would work.

 

[imasickboy]

Keezer is very small, fits two kegs and maybe a third 3 gallon one. No way to fit a bucket.

Find a container to fit in there. It doesn't need to seal, it just needs to hold water. Fill with immersible pump, water, drill two holes in your collar, (one out to stainless chiller, one return).

You're on the right track with your stainless pot idea, but I recommend perhaps a conical from US plastics. http://www.usplastic.com/catalog/item.aspx?sku=14062

An stc-1000 or inkbird, and you're good to go.

 

[SanPancho]

unless im missing something about you not wanting to damage/alter/cut into your keezer, i dont see why that isnt your best option. should be pretty cheap too.

you said it holds two kegs and another small 3 gal size keg? i assume you mean corny kegs, at which point you can just use the 3 gal keg as your cold liquor tank. open up the posts, take out the poppets and springs. then just drill holes in keezer wall, run tubing lines to the IC and then back into the cold corny(maybe insulate the tubing?), and just splice in your temp controller/pump assy between the liquid out post and the IC. bingo.

cold corny--> temp controller/pump assy--> IC--> return to cold corny.

3 gallons is a plenty good size temp reservoir for a normal 5 gallon batch. if you make sure your pump is sized correctly, there's no reason some 40-45F water wont be able to cool down wort that's in an ambient 65-70 degree range. how precise? cant say, but it will definitely work in terms of providing a big enough temp gradient to cause cooling of wort.

this is exactly the setup used by glycol jacketed fermenters in commercial settings..... just no glycol and using IC instead of jacketing.

easy peasy.

 

[Bigdaddyale]

Wrap the fermentor with a reptile heater then cover with insulation and place in the freezer. Control the heat wrap tempts.with a STC 1000 and just plug in the freezer

 

[jfr1111]

unless im missing something about you not wanting to damage/alter/cut into your keezer, i dont see why that isnt your best option. should be pretty cheap too.

you said it holds two kegs and another small 3 gal size keg? i assume you mean corny kegs, at which point you can just use the 3 gal keg as your cold liquor tank. open up the posts, take out the poppets and springs. then just drill holes in keezer wall, run tubing lines to the IC and then back into the cold corny(maybe insulate the tubing?), and just splice in your temp controller/pump assy between the liquid out post and the IC. bingo.

cold corny--> temp controller/pump assy--> IC--> return to cold corny.

3 gallons is a plenty good size temp reservoir for a normal 5 gallon batch. if you make sure your pump is sized correctly, there's no reason some 40-45F water wont be able to cool down wort that's in an ambient 65-70 degree range. how precise? cant say, but it will definitely work in terms of providing a big enough temp gradient to cause cooling of wort.

this is exactly the setup used by glycol jacketed fermenters in commercial settings..... just no glycol and using IC instead of jacketing.

easy peasy.

I don't have a 3 gallon corny, I'm just gessing a 3 gallon corny would fit on the hump. I would also like not to drill holes either. A collar is a possibility in the future though.

Maybe I'll just buy a small freezer than fits a single fermenter though (and hide it somewhere, ask for forgiveness after buying it), might be less costly.

I do like the idea of the stainless brewpot as a cheap brewbucket though.

 

[Bellybuster]

just to kinda go in a different direction.... your girlfriend wouldn't be happy with a small neutral looking refrigerator but would be fine with a cooler full of ice, a fermenter possibly in an insulated box or wrapped in some form of insulation and insulated tubing going between the two.... and a controller too. All of that can go inside a small fridge and take up less floor space.

I say forget everything above and go have a sit down with your girlfriend

 

[Bellybuster]

a freezer has zero potential energy....just for interest

 

[Stealthcruiser]

a freezer has zero potential energy....just for interest

I was thinkin' the same, just a good bit of "thermal mass".

 

[christyle]

My mistake, I was confusing the terms in my head. Ice has no potential energy as it needs energy to change into a liquid state. Ice is more a vacuum of energy, pulling the heat energy from the new, warmer object in the freezer. Put a warm item in a freezer and the more items there are in there, the more opportunities to pull heat from it.

 

[jfr1111]

just to kinda go in a different direction.... your girlfriend wouldn't be happy with a small neutral looking refrigerator but would be fine with a cooler full of ice, a fermenter possibly in an insulated box or wrapped in some form of insulation and insulated tubing going between the two.... and a controller too. All of that can go inside a small fridge and take up less floor space.

I say forget everything above and go have a sit down with your girlfriend

Fermenter would go into that out of sight room's closet, which cannot fit a fridge/freezer (no electrical socket, weird shape), while the ghetto setup would fit (barely) using a vertical structure. Which leads me to my next point.

I went back to the drawing board during lunch and thought about insulating that closet as best as possible using foam panels and using the guts of a small fridge/AC to turn it into a fermentation chamber. I could fit three buckets in there with shelves... There would be no way to individually control each bucket's temperature, but it would insure a cool, constant temperature without having to bring the temperature of a whole room down.