Space effective fermentation Chamber cooling?

[max384]

Within the next month or so I'll be building a dual-chamber fermenter. One for lagering and one for ales. I plan to make a fairly large one, with each chamber capable of holding three to four buckets/carboys. This is going to be fairly large and take up a lot of space in my garage.

With this in mind, I want to decrease the footprint as much as possible. I see the mini-fridge chambers all over the internet, but there seems to be a lot of wasted space doing it this way. What I mean is that the door is taken off of the fridge, and then the mini fridge is used to cool the chamber built around it. This effectively makes the entire mini fridge area wasted space.

I realize that I could decrease the size by cutting off part of the front of the fridge... But I really have no idea if the cooling coils run along the sides of any given fridge. If anyone knows any specific models where the cooling coils are only on the back, so I could really just cut off the entire front, that would probably be the answer. I'm assuming that would probably have to a fridge-only model (no freezer)

Is there another method of cooling that would save space that I'm overlooking? I thought of a window AC unit (and bypassing the thermostat), but I think that would likely take up as much space as a mini fridge, and I'd have to deal with the water dripping from the unit.

Any ideas?

Secondly, if a cut-down mini fridge is the best option, would that be large enough to cool a chamber large enough for three to four buckets/carboys? I'm planning on the interior dimensions being about 30" x 30" x 30", which is about 15 cubic feet. Most of the mini fridges I've seen listed for sale without freezers are in the range of 2-3 cubic feet. I'm sure these would work just fine for the ale chamber, but I don't know how they would work for lagering temps.

Maybe the answer is simply better insulation? Say 2" R10 foam board all around? Maybe add another half inch to an inch to make 3" of insulation?... But then that is increasing the footprint of this fermenter...

For the sake of argument, let's pretend that money is not an object. Of course it is, but I want to hear all ideas, not just the budget ones.

 

[max384]

Nobody? Cmon! I'm impatient with a short attention span. Oh look, a squirrel.

 

[actionjackson905]

Squirrel?? Where???

Short on time so I'll go for it as short as possible. Using mini fridge to cool a larger space probably won't cut it. You'll probably burn out the motor in short order. The chiller coil/plate is designed to cool the small space of those fridges.

if money is no problem, I'd go with a stand up fridge of the industrial variety. Like a restaurant fridge. Max space, good design. And you'd probably be able to 4-6, 5 gal pails in them. Plus the shelving is designed to hold that kind of weight. And their footprint is way smaller than a freezer, you could essentially have 2 side by side and take up the same footprint of a large chest freezer. Use one for lagers and the other for ales.

I'll be over for my pint when the first batch is... SQUIRREL!!!!

 

[kombat]

My $0.02:

I think this is a bad idea. Think it through. You say you want it to be big enough to hold 3-4 carboys and/or buckets. To which one will you attach the temperature probe to that controls the on/off of the chamber? And what happens to the remaining fermenters? They're just along for the ride? What if one has been fermenting for 4 days and is winding down, and you add a "fresh" one and attach your temperature probe to it. The "fresh" one begins actively fermenting (and producing heat), so the temperature controller runs the refrigerator unit to cool it back down. Meanwhile, your 4-day old one (whose temperature you should be increasing to encourage the yeast to finish up) isn't generating comparable heat, and thus gets cooled substantially, putting the yeast to sleep and potentially causing a stuck fermentation, or at least leaving behind a bunch of undesirable byproducts that the yeast would have otherwise processed, had you not chilled them.

Or perhaps you weren't planning on tying the temperature controller to any specific fermenter? Were you just going to have it measure the ambient and control that? Once again, this is inaccurate, as an actively-fermenting batch of beer can be up to 10° F warmer than the surrounding ambient temperature.

All this to say, I think such an idea is impractical, inaccurate, and clumsy as a fermentation chamber. Maybe as a storage unit from which to serve beer, but in that case, why not just use a good-sized chest freezer like the rest of us?

My fermentation chambers only ever hold a single batch of fermenting beer at a time, to ensure I can accurately and tightly control the temperature during those crucial first few days. That's the secret to making good beer.

 

[actionjackson905]

I'm with kombat on this one after reading his comment.

I have 4 mini fridges. I use 2 as chambers, one for ales and one for lagers. The other 2 I use as serving/carbing fridges. One I converted to a kegerator. I got 3 on kijiji, and the other was donated by a neighbour when he moved. Look for the ones with no freezer, and look when school ends. University and college students sell em cheap. You can even stack them I think. I put STC controllers in each of them btw.

 

[max384]

Squirrel?? Where???

Short on time so I'll go for it as short as possible. Using mini fridge to cool a larger space probably won't cut it. You'll probably burn out the motor in short order. The chiller coil/plate is designed to cool the small space of those fridges.

if money is no problem, I'd go with a stand up fridge of the industrial variety. Like a restaurant fridge. Max space, good design. And you'd probably be able to 4-6, 5 gal pails in them. Plus the shelving is designed to hold that kind of weight. And their footprint is way smaller than a freezer, you could essentially have 2 side by side and take up the same footprint of a large chest freezer. Use one for lagers and the other for ales.

I'll be over for my pint when the first batch is... SQUIRREL!!!!

I had looked into that, and it will just simply take up too much space, particularly the width. But I may end up having to go that route...

 

[jmpreiks]

I'm with kombat on this one after reading his comment.

I have 4 mini fridges. I use 2 as chambers, one for ales and one for lagers. The other 2 I use as serving/carbing fridges. One I converted to a kegerator. I got 3 on kijiji, and the other was donated by a neighbour when he moved. Look for the ones with no freezer, and look when school ends. University and college students sell em cheap. You can even stack them I think. I put STC controllers in each of them btw.

My ideal setup would also be separate mini-fridges that you can control individually. If you bought 4, you could build a simple 2x4 stand to stack them 2 high and take up not much room at all. You can stack them directly but I'd be hesitant with the weight of the fermenters inside.

 

[max384]

My $0.02:

I think this is a bad idea. Think it through. You say you want it to be big enough to hold 3-4 carboys and/or buckets. To which one will you attach the temperature probe to that controls the on/off of the chamber? And what happens to the remaining fermenters? They're just along for the ride? What if one has been fermenting for 4 days and is winding down, and you add a "fresh" one and attach your temperature probe to it. The "fresh" one begins actively fermenting (and producing heat), so the temperature controller runs the refrigerator unit to cool it back down. Meanwhile, your 4-day old one (whose temperature you should be increasing to encourage the yeast to finish up) isn't generating comparable heat, and thus gets cooled substantially, putting the yeast to sleep and potentially causing a stuck fermentation, or at least leaving behind a bunch of undesirable byproducts that the yeast would have otherwise processed, had you not chilled them.

Or perhaps you weren't planning on tying the temperature controller to any specific fermenter? Were you just going to have it measure the ambient and control that? Once again, this is inaccurate, as an actively-fermenting batch of beer can be up to 10° F warmer than the surrounding ambient temperature.

All this to say, I think such an idea is impractical, inaccurate, and clumsy as a fermentation chamber. Maybe as a storage unit from which to serve beer, but in that case, why not just use a good-sized chest freezer like the rest of us?

My fermentation chambers only ever hold a single batch of fermenting beer at a time, to ensure I can accurately and tightly control the temperature during those crucial first few days. That's the secret to making good beer.

My thinking is that the only issue I could have is that I would have to drop the fermenter chamber temperature lower than desired temperature for the beers already in the chamber. There aren't any off flavors from fermenting beers too cold, other than Belgium beers and a few other styles that showcase higher temp'off flavors.' And in these cases, I would keep them inside my house where the temps are good for these styles.

For the vast, vast majority of my beers, my ales all ferment at the same temperature. So, having them all in one chamber would work nicely. Dropping the temp once in awhile for an actively fermenting beer for a few days shouldn't hurt anything.

What do you do with your beers after they leave your fermenter chamber, if you only do one beer at a time? Do you just not keep a big pipeline?

 

[max384]

I'm with kombat on this one after reading his comment.

I have 4 mini fridges. I use 2 as chambers, one for ales and one for lagers. The other 2 I use as serving/carbing fridges. One I converted to a kegerator. I got 3 on kijiji, and the other was donated by a neighbour when he moved. Look for the ones with no freezer, and look when school ends. University and college students sell em cheap. You can even stack them I think. I put STC controllers in each of them btw.

Maybe using four mini fridges to build a four chamber fermenter, each only holding one carboy, would be the way to go for me... I already have a four tap kegerator, so I don't need a serving/carbing fridge.

 

[max384]

My ideal setup would also be separate mini-fridges that you can control individually. If you bought 4, you could build a simple 2x4 stand to stack them 2 high and take up not much room at all. You can stack them directly but I'd be hesitant with the weight of the fermenters inside.

I may end up going a similar route to this. However, rather than stacking mini fridges, I'd rather build four chambers into a single cabinet. I just really don't like the look of a bunch of fridges in my garage. I already have a kegerator and an upright freezer... Any more and it's going to look like I'm in the body part business.

 

[max384]

Thanks for all the advice and suggestions so far guys!

 

[iijakii]

There are builds on here of side-by-side fridge/freezer units. People mod them so the freezer side is set to keg temps (or could kick it up to ferment lagers) and then have a damper/fan hooked up to an STC to keep the fridge side at ale ferm temps. Seems like such a great setup.

If you get a big enough enough (25 cuft maybe?) you can fit a couple carboys on the freezer side and then easily 4 on the right.

Alternatively, two separate cabinets with AC units. Could build it into the bottom of a workbench or something for space-effectiveness.

 

[jmpreiks]

I may end up going a similar route to this. However, rather than stacking mini fridges, I'd rather build four chambers into a single cabinet. I just really don't like the look of a bunch of fridges in my garage. I already have a kegerator and an upright freezer... Any more and it's going to look like I'm in the body part business.

Ha, agreed. A cabinet with doors will definitely look nicer, especially with random CL fridges. Just make sure that you give plenty of space around the fridges and probably some ventilation fans. I know the sides of my mini fridge get pretty toasty when cold crashing.

 

[Bellybuster]

this is precisely where a glycol unit comes in. Each fermenter can be individually controlled with one cooling device.

 

[kombat]

There aren't any off flavors from fermenting beers too cold

Of course there are. US-05, for example, is widely known to throw off peach flavours when fermented on the cool side. In addition, any yeast fermented too cold could give up early and go to sleep prematurely, leaving residual fermentable sugars, resulting in an overly sweet beer (stalled fermentation). And as I mentioned in my other post, you could put them to sleep before they finish cleaning up after themselves and processing things like diacetyl or acetaldehyde.

Surely you can't really believe that the same beers, one fermented at 65° F and the other at 58° F, will taste identical?

For the vast, vast majority of my beers, my ales all ferment at the same temperature. So, having them all in one chamber would work nicely.

I still don't think you understand. Beer's temperature is dynamic. Fermentation is exothermic. As the yeast become active, they produce heat. So the fermentation chamber will have to lower the temperature to keep the fermenting beer's temperature within the desired tolerance. As the yeast run out of sugars, they'll calm down, and produce less heat, meaning the fermentation chamber will back off a little, and the ambient temperature will rise.

Two identical beers, fermented with identical yeast, but started 2 days apart, will be at very different temperatures. Simply holding the entire chamber at 65° F ambient is insufficient. The "newer" beer will get too hot.

Heck, even small things like a variation in how much yeast you pitch will affect the temperature schedule of the beer.

Dropping the temp once in awhile for an actively fermenting beer for a few days shouldn't hurt anything.

Except, as I said, risking a stalled fermentation (read: overly sweet beer) or putting the yeast to sleep before they have a chance to clean up fermentation byproducts (read: off flavours).

What do you do with your beers after they leave your fermenter chamber, if you only do one beer at a time?

I have 2 fermentation chambers, and if the need arose, I could cram all of our frozen food into one freezer and press a third into service temporarily. But after 7 days of temperature-controlled fermentation, I remove my carboys from the fermentation chamber and allow them to warm up to ambient room temperature to finish cleaning up after themselves. That frees up my chambers for 2 more batches, allowing me to brew 2 batches per weekend. After 2 weeks at room temperatures, the beers are kegged and go into a temperature-controlled chest freezer to carb up for 2 more weeks. My pipeline is 10 kegs deep.

 

[max384]

There are builds on here of side-by-side fridge/freezer units. People mod them so the freezer side is set to keg temps (or could kick it up to ferment lagers) and then have a damper/fan hooked up to an STC to keep the fridge side at ale ferm temps. Seems like such a great setup.

If you get a big enough enough (25 cuft maybe?) you can fit a couple carboys on the freezer side and then easily 4 on the right.

Alternatively, two separate cabinets with AC units. Could build it into the bottom of a workbench or something for space-effectiveness.

Converting a side by side would be a pretty attractive option. I'll look into this. Thanks!

this is precisely where a glycol unit comes in. Each fermenter can be individually controlled with one cooling device.

This is something else that I'll have to look into. Thank you.

 

[max384]

Of course there are. US-05, for example, is widely known to throw off peach flavours when fermented on the cool side. In addition, any yeast fermented too cold could give up early and go to sleep prematurely, leaving residual fermentable sugars, resulting in an overly sweet beer (stalled fermentation). And as I mentioned in my other post, you could put them to sleep before they finish cleaning up after themselves and processing things like diacetyl or acetaldehyde.

Surely you can't really believe that the same beers, one fermented at 65° F and the other at 58° F, will taste identical?



I still don't think you understand. Beer's temperature is dynamic. Fermentation is exothermic. As the yeast become active, they produce heat. So the fermentation chamber will have to lower the temperature to keep the fermenting beer's temperature within the desired tolerance. As the yeast run out of sugars, they'll calm down, and produce less heat, meaning the fermentation chamber will back off a little, and the ambient temperature will rise.

Two identical beers, fermented with identical yeast, but started 2 days apart, will be at very different temperatures. Simply holding the entire chamber at 65° F ambient is insufficient. The "newer" beer will get too hot.

Heck, even small things like a variation in how much yeast you pitch will affect the temperature schedule of the beer.



Except, as I said, risking a stalled fermentation (read: overly sweet beer) or putting the yeast to sleep before they have a chance to clean up fermentation byproducts (read: off flavours).



I have 2 fermentation chambers, and if the need arose, I could cram all of our frozen food into one freezer and press a third into service temporarily. But after 7 days of temperature-controlled fermentation, I remove my carboys from the fermentation chamber and allow them to warm up to ambient room temperature to finish cleaning up after themselves. That frees up my chambers for 2 more batches, allowing me to brew 2 batches per weekend. After 2 weeks at room temperatures, the beers are kegged and go into a temperature-controlled chest freezer to carb up for 2 more weeks. My pipeline is 10 kegs deep.

I honestly think you're making a mountain out of a mole hill. I've never had a problem with a stuck fermentation, other than a 15% barleywine, but that was not temp-related. In the winter, my beers definitely ferment 'too cold,' and that just means they take a bit longer. Not a big deal at all. If one gets stuck, so be it. Not the end of the world.

As far as off flavors from being too cold, the peach flavor with US-05 is the exception, not the rule, and even with US-05 there are more reports of no peach flavor than having them when fermented at low temps. I'm not saying two beers brewed at different temps will taste the exact same. What I am saying is that there will be no appreciable difference (as far as I'm concerned) in a beer fermented at a certain temp, and then dropped to a lower temp for a few days while another one is actively fermenting. If I were to raise the temp for a few days, that would be a different story.

The reason I am building a ferm chamber is to control the active fermentation temps, keep all of my beers from high temps, and to lager beers.

And I DEFINITELY don't subscribe to the notion of raising the temps to room temp to clean up a beer (other than diacetyl rest in lagers, which isn't room temp, and is another story entirely).

I appreciate your thorough, well thought out response, but I think we have differing opinions on this matter, and this isn't really an aspect of this build that I am looking for opinions on. I know I may sound like a dick, but that's not my intention. I just don't want this discussion to get sidetracked into whether my projected chamber size is too big or not.

 

[kombat]

And I DEFINITELY don't subscribe to the notion of raising the temps to room temp to clean up a beer (other than diacetyl rest in lagers, which isn't room temp, and is another story entirely).

Have you ever read a book on brewing?

 

[max384]

Have you ever read a book on brewing?

Sure have. Warming up an ale to room temp for cleanup is not a universally agreed upon step.

 

[kombat]

"Room temp" is of course subjective, but the practice of allowing a beer (ale or lager) to warm up towards the end of fermentation to encourage the yeast to clean up is indeed universally recommended.