Why I switched back to an Immersion Wort Chiller By: Tom Ayers

I started my brewing career years ago the same way many of us did, with a sink full of cold water.  When I needed to get the temperature of my wort down to pitching temperatures I filled up my sink over and over again with cold water and finally dumped in the ice.  After clearing the freezer of all of the ice I had I was still lucky to be at 80 degrees, which is where I tossed in my yeast.

After a while I began to understand it is easier on the yeast to pitch it at the desired temperature for fermentation.  When you consider ales are ideally fermented in the 60’s (F) and lagers in the 40-50’s I needed to make a change.  I read a lot about chillers from immersion to plate to counter flow.  I heard the sirens call of the plate chiller.  It seemed easy, fast, efficient, and foolproof.  I went ahead and got one and then I got it I realized I needed a valve in my pot and ideally a pump, although it was not absolutely necessary.  Side note, I learned a valuable lesson....never place an auto siphon in hot liquid, it destroys the value.

I’ve used my plate chiller for about two years and it has done me well.  But I’ve found several things that have not worked in my favor and as I’ve advanced in my homebrewing. I’ve found the need to move to the immersion chiller.  Now I get that this is the wrong “direction” when most brewers think about chilling.  Most would say the natural progression is ice bath, immersion chiller, then plate/counterflow chiller, after all that is what the pros use right?  Well, for me it was not.  And remember pro brewing and homebrewing aren’t always identical.

For reference here are two pictures of my setup including the whirlpool arm that I recirculate the wort back into to create the whirlpool and the 50’ ½” copper wort chiller with garden hose connections.

When I want to get my beer prepared for the yeast there are several things I need to have to ensure a good wort for the yeast:

1.  Quick chilling to avoid the creation of DMS    

2.  Control to dial in the right pitching temp

3.  Clear the wort to ensure I have a clean end product

4.  Minimize or eliminate any potential contamination

When I really thought about it I came to the conclusion that the plate chiller really only did one of these things well, chill the wort quickly, and even then I could argue that it didn’t even do that well.  Let me address each of these and why I believe returning to the immersion chiller was the right answer to each of these.

When it comes to quick chilling and the avoidance of DMS my understanding is the wort need to get below 140F as soon as possible.  now the plate chiller will get your whole five gallon batch from boiling to 80-90 degrees as fast as you can pump the wort through it, say five to ten minutes.  This is great but the problem is the wort sits in the pot at near boiling temperature until it goes through the chiller potentially creating DMS along the way.  My new immersion chiller with whirlpool arm knocks the temperature down to below 140F for the entire back in a few minutes.  

For temperature the plate chiller is simplistic.  Pump the wort and the water in and outcomes chilled wort.  Typically my wort came out of the chiller around 80 degrees, then I would take the wort to my fermentation chamber and let it sit until it cooled to the pitching temperature I needed which would take hours, especially for a lager.  With the immersion chiller I can place the chiller in the wort and leave it there until it gets to the temperature I want.  If I want to get it really low I can pump ice water through the chiller to get down to lager temperature well into the 40’s.  This can all be done in 10-15 minutes as opposed to the hours of my wort sitting in the fermentation chamber without yeast which exposes it to infection.

When chilling one thing you want to have is cold break.  Cold break is the coagulation of proteins and other stuff floating in your wort.  This coagulation contributes to clean appearance, reduction in chill haze, and a clean flavor in lagers.  when you use a plate chiller the cold break occurs inside of the plate chiller and ends up in your fermentor.  While some break can be good nutrition for your yeast, too much can contribute to off flavors and be detrimental to the delicate flavor of lagers.  In fact with my plate chiller, if I was making a lager I would pump the chilled wort into a carboy, let the break settle, and then transfer into another carboy before pitching.  With my immersion chiller, I get the whirlpool going with the pump and whirlpool arm and place the chiller in the boiling wort.  When the cold break happens it is happening inside the boil kettle and the whirl pool is forming a cone of it in the center of the pot.  When I pump off my wort it comes out clear and relatively cold break free.  No worrying about transferring or the effects of the break on my end product, just simple clean clear wort ready for pitching.

Lastly, contamination which is by far the most important.  Unless you have a plate chiller that you can take apart (like the therminator) to clean, and you do so on a regular basis you really have no way of knowing if the inside of your chiller is clean and sanitary.  This always made me nervous.  I would pump oxi-clean through, soak, rinse, dry in the oven and I still wasn’t sure because I would get junk out of it the next time I used it.  With the immersion chiller you stick it in the boil with 10 minutes to go and the boil kills anything on it....sanitary guaranteed, all you have to do is clean it when you are done and you can see the entire surface.

In summary, I can say that the plate chiller gets the job done quickly, at least on the face.  But the immersion chiller get the job done nearly as quickly, but it does the job more precisely while leaving the cold break behind and reducing the likelihood of contamination.  Of course you can whirlpool a plate chiller and pump ice water through it, but I’ve tried these methods and they’ve not been as nice and easy as the immersion chiller.  In the end for me it is all about KISS, Keep It Simple Stupid!  Before you upgrade to a plate chiller consider the fact that you may already have the best chiller you will ever need!