Counter Flow Wort Chiller

Dec. 16th 2010

AKA: Inverse Flow Wort Chiller and Reverse Flow Wort Chiller

   This is one of those technical blogs. Someone once told me to write about what I know. We'll in order to do that I'll lose a lot of people. Not because it's too technical, but rather it's real boring. Counter Flow Wort Chillers are real technical and really boring, yet for some reason I can talk about them for hours. Can you believe it. A good place to start the discussion is why. Why did they ever figure they needed these things?
   An acquaintance of mine cools his wort by the addition of ice. He uses the bags of ice from Safeway so "it's sanitary."
   We'll, it's not sanitary, but he gets a good quality beer from it, and that's what works for him.
   Because cold at freezing temperature (-15 to 0 C) does not kill bacteria. Whatever bacteria that was in that ice when it was water is still in it. Sure bacteria doesn't grow at that temperature. It isn't even active, it's more or less dormant just waiting to get thawed out again. I know just enough to know that I wouldn't do it. I'm optimistic so really I'm hoping the best for his brew. Using ice to cool down your wart doesn't necessarily mean that your going to get an infection. It just means that you have a better chance of it, That's all.
   For my own brew, I like to take as little chance as possible. I sanitize everything with One Step Sanitizer, and I use a Counter Flow Chiller. That's about it. Those 2 things will help you reduce your risk of infection. The chiller itself is designed to keep the wort and the water from physically mixing while at the same time the heat is transferred from the wort to the water. It does this by separating the running water and the wort by thin copper plates. The water and wort flow in opposite directions so that the incoming hot wort is transferring heat to exiting water, and on the other side the exiting cool wart is transferring heat to the coldest flow of the incoming water. This means that you have cold water going in and hot water going out. Here's a simple diagram.

IN - Cold Water (40 to 50F)            (flow rate fast)               OUT - Hot Water (90 to 110F)
----------->Water Flow>----------->----------->------------>----------->------------->
______________________Water/Wart Barrier_________________________________

<----------<----------<-----------<-------------<-----------<Wort Flow<-------------
OUT - Cold Wart (68F)                    (flow rate slow)             IN - Hot Wort (180 to 200F)

  
   Notice how the hot wort is transferring heat to the hot water and the exiting cold wort as it leaves is transferring heat with the entering cold water. This allows for the wort and water to actually changes places heat wise.
   There isn't a 100% transfer, but you can drop the temperature of the wort from 200F to your target 65F is a matter of seconds while it is in the Wort Chiller. The Wort Chiller that I have has an inline thermometer in the wort exit line. This allows me to make small changes in order to adjust the water and wort flows. The heat transfer is done very fast but for a small amount of liquid. I use the 30 plate wort chiller also so it has a better efficiency than the smaller chillers. The wort chiller can chill the wort at .22 Gals/Min or about 10 gals in 45 minutes. This is much better than what I had heard about the efficiency on immersion chillers, however the biggest reason I chose to use a Counter Flow Wort Chiller is that the wort doesn't stay in the danger zone as long as when using the immersion chiller. While I should be careful here because the Danger Zone is actually 41F to 140F. So the wort will be in the Danger Zone even at 68F which is where I want it. Not only will it be in the Danger Zone it will be there for about an hour because it takes 45min to chill and 15min to aerate. On the other hand, there is a more dangerous part of the danger zone and that part is right in the middle. So my wort will not be at the worst temperature for more than a few seconds and on top of that, even though I have to wait an hour before pitching the yeast, immersion chillers and ice bath chilling methods can take as much as 5 times as long. With a very good immersion chiller I'd imagine it would take a could of hours to chill a 10 gal batch. I wouldn't know because I never used an immersion chiller. How can I dis it before I try it? I know. Shame on me. I just can, because well I like to read.
   There are a lot of benefits to the immersion chiller. It has stood up to the test of time. They're cheaper and almost everyone has used them. They are easy to use and very intuitive. To tell you the truth I didn't know for sure how the Counter Flow Chiller would work when I first tried it. When It's all hooked up there are hoses going everywhere. I have to use clothwire hangers and cable ties to keep the hoses from kinking, and you have to clamp each hose to the barbs or else you'll get some leakage. There's also a lot of set up involved, which could be a little difficult for one person while finishing up the boil. I like the mess of hoses, and the tightening of the clamps, and the fine tuning of the water and wort flows. It's the building of something mechanical and almost alive out of fittings, hoses, clamps, and cable ties. It lets me get my Franken Stein out. I named my Beer Stein Franken.
   I guess that a huge part of my beer making process is the ability to DIY everything that you possibly can. The Counter Flow Chiller that I have is manufactured. This is simply because I had no idea that you could make one until after I had bought it. They cost about $100 to buy but I think it is well worth it. The In line Themometer was another $45, and all the barbs and fittings were another $20 so it does start to get expensive fast.
   If you want you can make a counter flow wort chiller. It will look nothing like the manufactured ones however I have a feeling that it will work better depending on how it's made. In the end it will look very similar to an immersion chiller except it wont go in the wort, the wort will go in it. Here's a place that will discribe how to make your own Counter Flow Chiller.

http://www.thegatesofdawn.ca/wordpress/homebrewing/wort_chiller/

   So you can see that making your own Counter Flow Chiller is completely doable. There is some soldering involved, but the hand held propane torch you need only costs about $10 at your local hardware store, and learning how to solder shouldn't take more than a day at the most. I actually like the DIY design a little better than the manufactured one I use because the design is a little different. The manufactured on uses plates while the DIY uses a copper tube. With the plate design there is more chance that trub can get stuck in the plates and cause it to plug up. I can't imagine that this would be much of a problem for the DIY chiller.

Jan 14th 2013
I've found a place on line that supplies a great counter flow chiller for a great price. This is the type of chiller that I would buy if I needed to upgrade to something other than what I currently have.

Counter Flow Wort Chiller by NYBrew Supply

I have purchased one of these Wort Chillers for a friend of mine, and it works good according to him. He has a direct comparison between this chiller and the plate chiller.