Saturday, November 24, 2007

DIY Wort Chiller

In search of ever faster cold breaks, my wife and I thought a wort chiller would help. One trip to Home Depot and four hours later, here is the result.

What you are looking at is a chiller that is set up to use a water pump to circulate the coolant. Our idea is to circulate ice water through the chiller to increase its cooling capability.
The parts:

The water pump is in the middle, and is being re-used from a fish tank. This is of course a great opportunity for contamination.

$26.53 20' 3/8" OD .0038" wall Copper tubing (Refrigerator grade)
$19.20 15' 8 gauge copper wire (wrong item - use > 8 gauge)
$04.44 10' Vinyl tubing 3/8" OD 1/4" ID
$04.40 3/8"x1/4" Compression coupler for attaching female thread to copper tube
$04.24 3/8" Male threaded 1/4" tube barb
$02.74 1/2" Male threaded 1/4" tube barb for water pump
$04.37 Reduction coupler for water pump

Amortizable/Borrowable items

$08.49 Tube bending tool (set of bending springs)

So for about $70 exclusive the water pump I got to waste an afternoon when I could have easily purchased a chiller for about the same!

Never mind the instructions, if you are intrepid enough to try putting one together, you are going to be able to figure it out. But here are the lessons learned:

- Never build your own wort chiller. Or, only build one for fun. It seems that it is hard to justify the cost and time.

- 8 Gauge copper wire is too difficult to work by hand. Get thinner wire. I suspended the loops of copper tubing by weaving the copper wire between the tubes, with two wraps per tube. I wound up (no pun intended) finding thinner copper wire around the house. Note the use of a spacer.

- Identify an object to use as a mold for this chiller tubing. Here, a 5 gallon PVC bucket perfectly fits in a small boil pot.

- The finalized wort chiller.

Additional points:
  • Clean the oil and dirt off the copper by using white vinegar.

  • When the copper wire is purchased, do not allow the store to tape or label the wire - the adhesive backing is difficult to remove from the wire.

  • Plan carefully the inlet and outlet - I sized the chiller against several different pots.

  • Consider drip loops for the inlet and outlet - in the picture above, they appear at a ninety degree angle, but condensate and leaks are going to clearly slide down the neck into the wort. Consider pointing the inlet and outlet downwards.

Results from having used the chiller:

  • First off, the boil is HOT. If you DIY a chiller, consider that heat conducts and the entire apparatus will come up to temperature. In our first usage, we threw the chiller in during the boil to sanitize it. The result is that the vinyl intake/outake tubes practically melted. Next time, we will first sanitize the chill with iodophor and remove the heat before immersion.

  • When the chiller was placed into the boil, it immediately refluxed. This is an important point to your DIY design - the air and remainder water from testing remains inside the chiller. When immersed, the air rapidly expands and remaining water gurgles out the intake and outake. Of course if you are connecting it to mains, this is less a problem. We are using a water pump which had to fight head pressure from the expansion of air.

  • Though the vinyl is tough, it will chemically alter from the heat and our chiller's vinyl tubing near the copper now has a pretty good haze.

  • The vinyl tubing is connected to barbs. When heated from immersion in the boil, the barbs were no longer effective in anchoring the vinyl tubing and minor leakage occured.

  • Apparently compression fittings need LOTS of compression - ours leaked slightly risking wort contamination.

  • Thought I planned carefully the inlet and outlet, you cannot leave too much - the heat conducts across copper like crazy. Leave at least a foot!

  • The next time we use this chiller, it is going to work really well. Maybe the beer master will post the temperature curve for us...

- Detail on the vinyl tubing - note the steam refluxing into the lower tube. Keep the flow going on immersion! The vinyl became quite soft and there was concern it would fall off the barbs.

- the whole setup in action! The main lesson is to bring the temperature down with mains water from 120 to about 90 and then to throw ice in and bring it down from 90 to the objective temperature. We had lots of ice, and it melted quite quickly!


Rich Andrews said...

The wort chiller has been deployed on a Czech Pilsner! The results are quite good, so I've updated the original post.

courcaci said...

Nice job !! good looking result :oP

Im looking foward to make one but now after reading your advice im reconsidering it.....

DO you thing there is a cheaper way to get good result ?

Bot and me said...

Interesting post. Thanks for the share.
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Joel Ohmer said...

Quite interesting! Living in South Louisiana, where the "cold water" coming from my tap is probably 80 degrees during the Summer months, this will greatly decrease our chilling times.