Multi compartment/chamber keezer

I’ve just started on this brewing path, but, as with everything, I like to start things the right way. After a lot of reading I would like to ferment my beer in a corny keg and use a keezer for both fermenting and pouring it.

So my idea was to get a chest freezer and use it as both a fermenting chamber and to pour beer. And using the Spark 4 for temperature control.

My plan was to get heating pads for each compartment and control those with a Spark 4. If the compartment walls are sufficiently insulated, would I be able to have 3 different temperatures in each compartment? And can the Spark 4 do this?

You can only do 1 setting with cooling of course, the difference in temperature would be made up with heat pads I guess driven by the temperature meters. Can I tell the Spark 4 how many degrees I want each compartment?

As for the heating pads, I was thinking about the following:

So a fake wooden bottom with a fan (blowing up) and a heat pad under it, controlled by a Spark 4.

Does this sound ok? And how much W does a compartment need?

Technically this can be done: get the cooler to act on whatever keg should be coldest, and attach heating belts with separate heating control chains to each keg.

Practically, this system is unlikely to be anything approaching stable. It will have significant overshoot both ways, and will achieve steady state equilibrium by running the heaters and the cooler at the same time.

To have a system with the least hardware for multiple managed entities, I’d suggest glycol. You can use a central pump and reservoir, and control cooling for each keg with a dedicated valve.

I am the originator of the “Mother of All Fermentation Chillers”. You can google it, but the only pictures that come up are from a guy on HomeBrewTalk that made one. Mine was the “furniture grade” one he mentioned… I was in the same head space as you - about 13 years ago. I saw all the wasted space above my chest freezer as an opportunity. I never liked the idea of putting a heater INSIDE my fridge to let them fight it out, while I paid the power bill… I built a large wooden box, with two doors that swung out, and had some “trap doors” to access the serving kegs. I didn’t have two different chambers for two different fermentation temps. Wasn’t necessary. Since heat rises, I didn’t tax my freezer. I just turned on two 120mm fans to suck the coldest air up, and replace it with the warmest air down. You could add a “third layer”, but that would be too high up to comfortably move carboy around. I did have a “two stage” Johnson control on there when I wanted to do ales in the wintertime (it was in my un conditioned, un insulated garage). It drove a small wattage “reptile heater” pad. The input temp was always taken by taping a probe to the outside of the carboy (and insulate it from the ambient).

It worked great until the freezer died, a few years later. I managed to find one similarly sized. That also died a few years later. Chest freezers aren’t serviceable. They are “disposable”. When they pop, they are garbage. Besides the really harmful effects on the planet - there were other problems that forced me to reconsider splitting my fermentation and serving needs. If a keg blew while I was fermenting, it was a pain to shuffle the carboys around so I could pull out the empty and replace it. It wasn’t easy to get those kegs out of the bottom, either.

If I could talk to a younger version of myself, I’d say to just find the space and money for a dedicated fermentation fridge, separate from your serving fridge. And buy commercial fridges if you can. They are almost infinitely serviceable when some component dies.

Your design puts heaters inside the cooler. Don’t do that. The only one that wins there is the power company…

Side note here that for a single heater inside a fridge, this issue is solved in software. If the heater or cooler is activated, the other one is locked out for long enough to prevent pull/push behavior.

Thank you all, your advice has been most helpful. There’s a lot of information to take in when starting out.

For now I’ll focus on the fermentation side of things and won’t try to combine that with pouring the beer.

Or do what I did:
Buy an inline tap cooler with a cooling coil like the Lindr AS-80.
My kegs are at 20C and are cooled to serving temp in a single pass by going through the coil and a cooled beer line (python).
I have 2 extra pumps in the water reservoir that pump water through the coils in my fermenters to regulate those.

Added bonus is that I can bring multiple room temperature kegs and the chiller to a party and serve cold beer anywhere. More mobile and more space effiecient than a keezer.

That does look very nice indeed and I’ll take it in consideration for a bit later.

I just started to think about brewing and getting the start-up equipment for that. Start-up equipment as I think is best after reading a lot, so not always the cheapest options. But I’m still Dutch and worked in IT before I migrated to New Zealand, so I like to fiddle around a bit with tech.

For now I’m off to another brew festival in Wellington, Beers at the Basin.