Glycol Chillers

With the move to increase my beer capacity via a 1BBL SS Brewtech Unitank it was going to be unpractical to control temperature using a converted fridge due to the size of the unit. In my previous home brew setups, I had relied on a couple of glass carboys being stored in a fridge where I controlled heating (a light bulb) and cooling (the fridge itself) using a temperature controller that I DIY’d – it wasn’t pretty, but it did the job.

So the next plan was to come up with a glycol chiller, what commercial breweries use to cool fermentation temperatures and crash cool large volumes of liquid. Unfortunately at the time SS Brewtech’s glycol chillers weren’t available in the country at the time (and indeed, might not yet have gone to market) so I dropped into the guys at Absolute Control in Petone. They recommended heading over to Stowers and picking up a 100L plastic insulated box that is commonly used in the fishing industry, bring it back to them and they’d add the appropriate coils and compressor to make sure it had enough thermal capacity to easily cool the unitank (and future unitanks). And so what was called ‘big blue’ was born.

It’s fair to say that it wasn’t quite what I was expecting, and not having given any specifications of what I was looking for, it took up a huge amount of real estate in the brewery. I had no doubt it would do the job, but was in a quandary about where to store it. The box would hold 30-35% food grade glycol, 65-70% water mixture that would be rapidly cooled by the copper coils carrying refrigerant through them. But ultimately having the reservoir side by side with the compressor was deeply impractical. One thought was to get Chris Banks to weld up a stainless steel frame and get the guys at Absolute Control to de-gas and refit to the new frame.

Fast forward several months/years of not entirely giving up on it (even to this day it’s still up in the shed in the hope that it will get some use at some stage) and the SS Brewtech glycol chillers are available via Brewshop. They come in 3 different sizes – 1/5HP, 3/8HP and 3/4HP – accounting for the different sizes of thermal capacity (18L, 38L and 83L reservoirs) with the appropriate compressor to match. To avoid some long standing disagreements about the aesthetics of big blue, I was encouraged to order one. I chose the 3/8HP version, despite being a step down on the original chiller that Absolute Control had built.

The chiller itself is a nice piece of compact engineering and being on casters makes it easy to move around. The reservoir sits onto of the compressor, a design I had originally hoped would magically evolve with big blue. There’s an easy to use controller to set the temperature and a series of terminals on a removable panel at the top.

With the SS Brewtech FTS controller, you simply submerge a pump into the glycol reservoir and an external controller decides when to pump the glycol solution through the inside of the stainless steel chiller coil within the unitank. I decided to fit some quick release valves to this end for convenience during cleaning the fermenter.

In my experience so far, the glycol chiller has done an excellent job of maintaining fermentation temperatures and also the ability to crash cool after fermentation. The added benefit is that it’s also been super handy to bring warm wort down to a pitchable temperature as my current hot side stainless steel counterflow chiller isn’t doing a great job in that regard. I haven’t done any explicit timings yet, but know that I can go from about 40C to 20C in no time which is usually the time I leave the fermenter before pitching the yeast so I can dump whatever trub I’ve picked up during the transfer.

The FTS controller kit also provides a small heating jacked that fits right at the bottom of the cone in the unitank. When the temperature probe detects the beer needs to be cooled it will start the pump and circulate the glycol. When it needs to be heated, the heating jacket will turn on. For a home brew setup, that’s super convenient and means that I can brew pretty much any beer with some different fermentation profiles. With the fairly recent introduction of SS Brewtech’s jacketed unitanks I’m not 100% sure how you’d be able to have the same flexibility without some ability to have a warm glycol loop.