For the Love of Fermentation

[SimonSaysBrew]

Hi guys,

I struggled with the fermentation temperature control issue for quite some time. A while back I was able to obtain a 7.5 gal conical on ebay but my keezer was too short to handle it. What to do? I didn't want to buy another freezer or refrigerator so I decided to do what the big boys do, build a jacketed conical.

Conical fermenters are wonderful devices for saving labor and preventing exposure of your beer to nasties like oxygen, light, and undesirable microbes. Also, being able to bottom dump yeast, trub and dryhops with the turn of a valve handle is, well…… amazing. The problem is that most of the chest freezers out there will not handle a conical fermenter. They are just too short. Enter the jacketed conical.



The components for this build are fairly straightforward. You need a source of cooling, a pump, a heat exchanger, and a temperature controller. In addition to these components you will need various fittings and copper piping to deliver your coolant to your fermenter. I, after some trial and error, settled on a 1/3 hp aquarium chiller as my source of cooling. These chillers offer in line chilling and can be had on ebay or craigslist. I found mine on craigslist for $190.



For my pump I chose a variable speed Grundfos UPS 15-58 FC recirculating pump of the type used for radiant floor heating.




The heat exchanger is simply 25’ of ½” OD soft copper tubing. The copper tubing is wound around the conical and then insulated or “jacketed” with a recycled yoga mat or some such insulator. To achieve a snug fit to your conical do two things. First, flatten your tubing a bit (not too much!!) using a piece of large diameter pipe. Roll the larger pipe along your copper tubing until you achieve a uniform oval type shape the length of the tubing. This helps to increase the surface area in contact with your conical. Remember, DO NOT deform the very ends of the copper. You will need to sweat fittings on the ends and they need to stay nice and round. Second, wind your tubing around something round that is slightly smaller than the diameter of your conical. I used a 5 gallon bucket. The reason for this is that when you coil the copper it tends to rebound a bit and will hold a diameter slightly larger than the object you coil it around. Ideally when you are finished your coil should be just a tad smaller than your conical diameter so when you install it you have to “spread” it a little and then it snaps back and grips your conical making good contact. For temp control I used an STC-1000 dual controller. I wired the box for heat and cool but, living in Arizona, I don’t have much use for fermenter heat.



(Note: This photo shows an initial configuration with the chiller on the other side of the wall. It didn’t work as there was just too much piping and heat gain during the hot months here in AZ.)



Putting it all together. This is where some basic plumbing and wiring skills come in handy. You’ll need to configure your piping so as to make a cooling loop that is preferably as short as possible. The longer the piping runs, the more cold you will lose to the surrounding environment. My system is set up as close as I could get the components together. It can consistently cool the fermenting wort to 20-25º below ambient. The trickiest part of the plumbing is deciding how to configure the system so that you can prime your pump without to much hassle. I still haven’t perfected this aspect but I used a filler neck with a shut off valve that sits higher than my pump and it works ok. The actual loop theoretically starts at the output of your pump and makes its way to the top of your cooling coil on the fermenter. I used plain old ball stop valves and braided faucet supply lines to transition from the hard copper on the wall to the coil on the fermenter. Note: ½” rigid copper and ½” soft copper do not share common dimensions so when shopping for fittings be sure to test them on the soft copper and use adapters or reducers as required. Now the coolant flows through the coil and exits at the bottom of the fermenter coil through another braided line to the hard copper return line to the intake of the pump. This is your basic cooling loop. Notice that I omitted the inline cooling source (in my case an aquarium chiller). The chiller may be located pretty much anywhere in the loop and mostly depends on space and the geometry of where you locate your system. I have successfully put the chiller upstream and downstream of the pump. Installing your chiller will require some fittings to accommodate the different size tubing of the chiller and your loop (I used ½” copper for the loop with various fittings to connect to the pump and the chiller) A little imagination and a few trips to the hardware store will get you there.



(Please excuse the bucket and tile fermenter stand. I needed to get a Two Hearted clone going ASAP and am still building out the fermentation room! Keeping the fermenter on a stand allows easy gravity powered racking.)

 

[SimonSaysBrew]

Wiring the STC-1000 has been covered quite a bit on various forums so I’ll leave that to those respective threads. You will need a thermowell for the STC temperature probe. I bought mine online for about $20. Drill a hole in the lid of your conical using a step bit large enough to accommodate a drilled stopper. The thermowell goes through the stopper and into the wort. Driling the lid requires patience and lubricant. Use cutting oil to lubricate your step bit and take your time. Stainless steel is hard stuff. Using a thermowell in the wort allows the STC-1000 to read the actual temperature of the fermenting wort rather than say the ambient tempereature of a fermentation chamber. The STC-1000 most often comes calibrated to Cº so tape a conversion chart to the wall next to the unit. Here the unit is set to 14ºC to start dropping yeast and dryhop into the cone in preparation for racking to a serving keg.



You should now be ready to test out your system. Fill the fermenter with room temp water and assemble the lid and insert the thermowell and temp probe of the STC-1000. You’ll need to prime the Grunfos pump to get it going the first time. I fill through the filler neck on the right and wait for the cooling liquid to slowly work it’s way to the pump. I use plain water in my system because the aquarium chiller doesn’t get below about 40º F. A more robust chiller may require the use of 50/50 propylene glycol and water. Once the pump is primed, turn your system on by setting a temperature on the STC-1000 to something below the water temp in the fermenter. I plug a power strip into the STC and then plug my pump and chiller into the power strip so everything kicks on at the same time. The pump only draws an amp or two so there is no issue with the STC failing to deliver enough switching power to the chiller. As the Grundfos starts to pick up fluid, you will need to continue adding fluid to top off the cooling system. I leave the filler neck valve open for about 30 minutes with the system full and running to allow air bubbles to work their way out of the piping.
With your system running it’s time to take a temperature reading and start a clock. My system can reduce 6 gallons of wort roughly 10º F in under 2 hours. Once it reaches it’s temperature setting it keeps it within 1º F easily. Typically it cycles on once an hour or less for about 15 minutes during cool weather and about twice that during warm weather. The room my system is in reaches 90º F during the summer and I can maintain 65º fermentation temps. A more powerful chiller would certainly be required to ferment lagers using this set up.
Hopefully this post provides some inspiration for other DIYers out there. As far as cost, I spent less than half of what the turnkey conicals from MoreBeer run. The fermenter was $300 (ebay), chiller $190 (craiglist), pump $75-90 (any plumbing supply website), STC was about $25 (ebay), 25’ of ½” soft copper $50 (Home Depot), and about another $75 in piping and valves etc.
So that’s my ale fermentation set up. I’m still lagering in buckets in a keezer but they don’t require quite as much attention as ales like big IPAs and Imperial Stouts etc. I hope you guys find this post worth the read.

Cheers!