Wednesday, May 2, 2012

Building an Immersion Chiller

I seem to be slowing down again on the brewing and blogging fronts.  Hopefully that will change soon as I am gearing up for a couple more brew days before the summer hits.  In the meantime, I just thought I'd share some info about building a copper immersion chiller.

As most homebrewers probably do, I started out cooling my wort in a sink filled with ice.  But as I learned the importance of chilling the wort down as quickly as possible, I decided I needed a better process.  Chilling the wort quickly accomplishes a number of things, including:
  1. Prevents the formation of DMS:  DMS (dimethyl sulfide) smells and tastes like cooked corn and is something you usually don't want in your beer.  It forms naturally from SMM (s-methyl methionine), which is found, in various quantities, in malted barley.  SMM is converted into DMS at temperatures above 140°F, so quite a bit of it can be formed during the mashing and boiling stages of brewing.  Fortunately, boiling drives off most of the DMS.  Once the boil is ended however, SMM will continue to be converted into DMS, but now the DMS is no longer boiled off.  So, the quicker you can get your wort chilled, the less DMS you get in your beer.
  2. Produces clearer beer:  When wort is chilled, haze-causing proteins coagulate and drop out of solution.  The faster the rate of chilling, the more these proteins coagulate and drop out.  The more these proteins coagulate and drop out, the fewer there will be in your finished beer.  The fewer of them in your finished beer, the less your beer will exhibit chill haze.  So, faster chilling leads to clearer beer.
  3. Gets you to yeast-pitching temps faster:  Once wort drops below about 140°F, it is susceptible to bacteria and wild yeast.  The quicker you can pitch the your yeast, the quicker you can get a controlled fermentation underway and the less likely you are to have bacteria or wild yeast take hold in the beer (as fermentation proceeds, the pH of the beer drops and the alcohol level increases, creating an inhospitable environment to unwanted microbes).
An immersion chiller is a great way to cool your wort down quickly.  It works on the same principle as the radiator in your car - by circulating a liquid though a set of metal coils in contact with a heat source you want to cool down.  The heat will be conducted by the coils into the cooler liquid and the circulation of the liquid will move the heat out of the wort (or engine), thereby cooling the wort (or engine).  Immersion chillers tend to be made out of copper since it is an excellent thermal conductor.  Since copper is so malleable, making your own immersion chiller is relatively easy.  Here's what I used to build a chiller to fit my 3 gallon kettles:

  • 20' of 1/4" (ID) x 3/8" (OD) flexible copper tubing
  •  10' of vinyl tubing
  •  2 hose clamps
  •  faucet adapter
All total, I spent less than $30.  Though with the price of copper today, you can expect to pay a little more.  As you would also, obviously, if you needed to make a bigger chiller to fit your system.  Here are a few photos of my build:

It works great - with this chiller I can get my wort cooled down to pitching temps in 15-20 minutes.  If I were to do this over again, however,  I'd raise and bend the input and output so that they would be out of the kettle.  The way it is now, if the hose clamps ever loosened up, I'd end up dripping straight tap water directly into the wort.  As it is, I just make sure the clamps are fully tightened before each use.


Ben Helms said...

That's awesome. Thanks for posting this. I've been thinking about doing this and I think with this great info I'll take the dive next week. Looks great!

Jim Lemire said...

Ben - glad this post might be of some use. It really was pretty simple to make - just make sure you're careful not to kink the copper, and, if possible, try to get the output and input up and bent out of the kettle. Good luck with your build.

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