Quadrachamber - Four Zone Fermentation Control

[MikeRussell]

Hello, HBT.

Hopefully I found the right section to post my fermentation chamber build - feel free to move or re-categorize if needed.

First and foremost, a HUGE thank you to the community. I've been lurking for quite some time. I am constantly impressed and have learned volumes by reading. Hopefully now I have something to add.

I hear it is common practice to show the completed project photos first so the lazies can peek without reading. Here goes:

The wife and I recently built a new garage and I was able to negotiate an addition for dedicated brewing space. My brewing system is out in the shop, but I ferment in a small basement room. I am constantly hauling carboys down stairs and then kegs back up a few weeks later so I can serve beer on draft out in the shop.

The basement room is temperature controlled by an STC-1000 and space heater. This works great for the most part, but some of my recipes call for yeasts that can create excellent flavors at higher temperatures. Other yeasts are happier when it is cold.

For this project, I decided I would like independent control over each batch so I could create ideal conditions for the batch at hand. Also, if I was able to ferment in the shop I would have a single location for brewing, fermentation, conditioning and serving. That would be pretty neat!

I like to brew 5 gallons at a time, and I like to brew often. I decided I want 4 independent zones so I can keep a rotation going.

After brainstorming a few solutions, I decided I wanted to start by purchasing mini fridges from Craig's List. I narrowed my search to 'cheapest fridges about 4 cubic feet' which is about what you need to fit a carboy. The smaller sized fridges can do pretty well with a little modification, but I wanted to be certain that the fridges I buy would keep up with 5 gallons of yeasty goodness.

In a day I was able to find and purchase all 4 chambers. Here's the before photo.

The one mini fridge came with a bunch of stickers I didn't enjoy - look how it barely measures up to the beer sticker fridge!! Hah! Anyone notice a sticker from where you're from?

When I bought the fridges, I knew only one of the them would actually fit a carboy so I planned on adding a 2x4 framed collar to each one. I wasn't super excited about the doors. A couple were decent but ultimately I decided I wanted to build custom doors so they would match the rest of the shop counters.

I started by removing the doors and building collars:

Then I created door frames and cut some blue foam (which was donated by a fellow home brewer!!) to insulate the new doors:

With the new doors assembled, I added handles and mounted them to the collars:

Then I needed to deal with some some temperature control guts. I did a little freelance development work a while back to create a temperature logger for a friend and posted the resulting applications online. Apparently it solved a problem for quite a few people, one person even sent me a free BCS (THANKS Oakbarn!!!) which is a big reason I kicked off this project.

For those who haven't checked it out, the BCS will monitor each carboy's temperature and turn on either a heating or cooling circuit based on the current set-point. The BCS also has a web interface so you can interact with it from a phone, tablet, computer or whatever you have that can view web pages. The BCS allows you to pre-program a fermentation schedule with multiple set-points over time.

Back to the build, I made a little control box to house my components:

This picture obviously isn't final - I had to run wires for four thermometer probes, power and ethernet in addition to the four outlets.

With thermometer probes dry fitted into each chamber, I was able to run some tests and make sure things are running as expected.

Then I built an adjustable tablet mount so I can visualize the current status of the fermentation chambers and make any adjustments as needed:

Which finally brings us back to the first and last photo, the status as of today:

In the future I plan to do paint/burn/stain some sort of design on the chamber doors. Probably something related to barley or hops, you know the story.

 

[MikeRussell]

I'm happy to report that I'm already using one of these chambers to ferment my first pilsner! Woot! Here's a copy of the current datalog for the chamber in use:

 

[pricelessbrewing]

Neat.

Question: How did you attach the extension to the frame of the fridge? Bracket on the inside?

 

[MikeRussell]

I used some heavy grade construction adhesive and squeezed it on thick! Liquid nails also works (and is cheaper) if you don't have easy access to NP1.

The majority of the carboy sits on the base of the fridge itself. The extensions can be sized to fit barely below the bottom of the fridge to make sure it doesn't have to hold weight. Not sure if that makes sense I might need to take a picture to help illustrate.

 

[pricelessbrewing]

Gotcha. That should work nicely. I followed, but more pics are also appreciated.

 

[MikeRussell]

update time!

I have been using the chambers for months now, with a ton of batches running through. Fermentations have been very smooth and I am really satisfied with the system. I think I have learned a few things to add to this thread:

-I decided to stain the trim around the edges and add a coat of polyurethane to protect the doors. I like how they turned out. See the image below.

-For cooling, I just run the fridge in question whenever the cooling setpoint is hit. This is managed by the BCS settings and you can make the heat/cool window as big as you want. Depending on how the chamber is heated and depending on your heat/cool threshold, you can easily make your fridge fight a heater for supremacy. Not very good for either device.

-Cheap mini fridges are, well, cheap. One of them already gave up the ghost when its compressor went out. I bet that fridge got into too many fights with a heating pad and the compressor was overused. Orrr maybe it was on its last leg when I bought it. Oh well.

-You should definitely add polyurethane to the wood on the inside of the chamber. Those chambers get wet pretty easily between blow-offs and condensation. So far I haven't noticed a ton of issues as I clean the chambers thoroughly after each batch, but wood is porous so only time will tell.

-For heating, I previously had cheap engine heating pads I found on eBay. These are designed to be attached to an engine to heat. I didn't have them attached to an engine, I just had them sitting in a fridge. They get very hot, very fast and as a result they started melting the walls/floors of the chambers. Then I stuck the heat pads to pieces of scrap steel and propped them inside the chambers. This seemed to help a little bit, but the heaters overheated and burned out very quickly.

-I eventually decided not to use engine block heaters, and purchased small space heaters from amazon. The cheap lasko 100 heaters are built to shut off at a certain temperature so they won't burn your house down. Since we're using the BCS460 as our thermometer, the temperature override in the heaters is useless. I opened up the heaters and bypassed the thermal override circuit so the heaters stay on when the BCS says so.

-I decided to purchase a cheap stainless kettle from AiH and ferment in the kettle. I got the 1-weld 8 gallon kettle and added a dip tube inside so I could transfer off the trub. This was a HUGE upgrade and I'm really happy with how it works. Transfers are really fast, blowoffs are rare - only on >10%abv beers in my experience - and cleaning is SO SO easy. This new idea means I may need to modify the chambers to hold a wider vessel. Also, I needed to find mini 1/2" valves as full 3-piece valves were too big to fit in the chambers as they stuck out too far from the kettle.

 

[drgonzo2k2]

Sorry, maybe I didn't parse your update correctly, but are you meaning that you run the fridge full time and have it set to kick on the heater when the temp drops below a certain point, making your fridge and heaters fight each other?

 

[MikeRussell]

Nope, the fridge only kicks on when needed. I'll try to edit and clarify that

The point I was trying to make is with a strong heater, you could overshoot your cool setpoint and make a fight as a result.