Saturday, August 18, 2012

Making a Wort Chiller

You only need to brew once to understand the value of a good old-fashioned heat exchanger!

After boiling all of the ingredients, the wort needs to cool to a temperature that won't kill yeast.  The tricky part is doing this in a truly clean fashion, and many new brewers are forced to use the kettle-in-an-ice-bath method.  The first time we brewed, it took us over an hour to cool our wort, since our bathtub was so huge and we didn't have enough ice.  In our new apartment, our brew kettle fits snuggly in the kitchen sink, which allows for frequent water bath changes and a wort cool down to happen in about 45 minutes instead.

This last month, Ryan took the initiative to fashion a homemade wort chiller.  Time for a science explanation!  A wort chiller is essentially a heat exchanger.  The idea is that the cold pipe and hot fluid will "exchange" energy, thus cooling your fluid and heating up your pipe.  We used a 25-ft copper coil because the more surface area you have, the more heat you can exchange through the pipe.  Additionally, copper has a high thermal conductivity, which means heat transfer occurs at a faster rate than materials with a low thermal conductivity (like air).  To keep the copper pipe at a much lower temperature than the wort, you run cold water through the coil to keep the heat exchange at a high rate.  This homemade chiller brought our wort cool down time to < 20 minutes.

The best part?  Ryan spent ~$30 on materials and a few hours in one day, and I bet we could have spent less if we did some deal-searching online/in town.  If you go to a homebrew store to buy a commercial wort chiller, they can run at least $60.

We purchased our materials from local hardware shops, but I linked some of the materials to so you can see the pictures.  Of course, it is best to have the pieces in hand to make sure everything fits before you go to put it all together.


Take out your boiling kettle and make sure the copper coil can fit inside.  Slip the tube bender over the pipe, and use your hands to shape a 90-degree bend such that ~8 inches of the tube protrudes over the top of the kettle.  Bend another 90 degree bend at the top of that leg, such that the pipe is parallel to the ground.
Repeat this with the other end of the pipe.

Cut your plastic tubing in half.  Affix each piece to one end of the copper pipe, and secure in place with a worm drive clamp.

With one of the plastic tubes, push the hose-to-barb adapter into the tube and secure with another worm drive clamp.
Screw the faucet-to-hose adapter onto the other side of the hose-to-barb adapter.

 Remove any sort of cover from your faucet of choice, and attach the faucet-to-hose adapter to your sink faucet.
Place the wort chiller in your kettle, and route the free plastic tube to a drain (we used our bathtub).

Now turn your faucet as cold as it will get, and watch your wort cool at record speed!