• CounterFlowChiller

Counter Flow Chiller Construction

see also ChillerGallery for pics of a variety of coolers.

Now before we get started, I would just like to say that even in Oz, it is possible to buy a brand new CFC for around $80 (+ postage). The model shown here cost more than that. I could conceivably have made it cheaper (say around $60) but if your justification for making a DIY CFC is on economic grounds then you will have to choose a design carefully.

Rolling the coil around a stock pot. This bit actually isn't too hard compared with making my immersion chiller coil, mostly due to the smaller diameter coil of the IC.

The general idea can be seen here. I cut a 3/8" roll of copper pipe in half. The 18m roll cost me $45 inc GST from Refrigeration Parts Victoria. I have seen prices more like $70 at plumbing stores.

The type of garden hose I chose was Nylex eclipse, I figured I would spend a little more since once the thing is put together, I don't want it to spring leaks in a hurry. Also I noticed it had a kind of rifled texture inside, maybe this will improve turbulence (purely speculation).

This shows the compression fittings used on the end (before I put the click-on connectors for the hose). I was originally going to use solder connections (see below). Compression fittings normally have a stop to prevent the pipe passing right through. I drilled out the 3/8" one so the pipe could come out the end.

Also, don't expect to be able to pull apart the compression fittings too easily. The "olives" that clamp down onto the copper compress it and are extremely difficult to budge. Also, don't tighten the 1/2" compression fitting too tight otherwise it will constrict the flow of the cooling water.

The other challenge is the coupling to the brewpot. What I have here is some nylex reinforced tubing (strictly not rated for boiling temperatures, but it is at low pressure). Now being the scavenger I am, I kept the ends of the "Easy Hookers" I destroyed to make mashtun braids (see BatchSparge). With judicious use of an angle grinder you can remove the barb and fitting from the rubber tube and pressed steel clamp. The neat thing about these fittings is that you can screw them on to half inch BSP thread without having to turn the whole CFC around. It will have a hose clamp when I go buy some.

Here is the flow I was getting in a trial with plain water, gravity feed with around 400mm head. It is around 1 litre per minute. The temperature of the "wort" coming out was 22.5°C (which is a degree or two above tap water temperature). I didn't measure the cold water flow but I had it turned down very low.

Since building it I bought a MarchPump and although I haven't measured the flow it is considerably faster.

An alternative T configuration I was considering. Cheaper but more permanent and there is the challenge of soldering it without melting the tubing. The 3/8" copper passes through the T with small tubular brass bushes to fill the gap.

CFC Cleaning

People have different approaches to cleaning their CFC's. Mine is like this:

1. Before brewing, recirculate pH 2 phosphoric acid solution through it for around 10 minutes.
2. After brewing, pump tap water through it until it runs clear (just a couple of minutes).
3. Recirculate with fresh phosphoric acid solution for 5-10 minutes (while I am cleaning up the other stuff).
4. If you are not going to use it for a while, don't leave the phos. acid solution in there. Rinse it out with tap water.

See CleaningAndSanitation for general info on this subject.

paul sorenson