The Technical Edge: Infected Beer? Your Counterflow Heat Exchanger is the Most Likely Culprit

Written by Steve Fried for Pensabrew News

I started home brewing in 1979 and went professional in 1989 when I started working at McGuire’s (Pensacola…. also Destin, FL… Irish theme restaurant/brewpub- Prof. GA) As an extract home brewer from the beginning, I finally experimented with all grain in 1988 and the beer was horrible, my worst ever, and I didn’t know why. It wasn’t until I started brewing at McGuire’s that I was to learn my fatal mistake. The heat exchanger had not been properly cleaned and sanitized. My trainer taught me the proper method I’m about to share with you. I credit this technique, which I followed faithfully for 12 consecutive years, for our clean ales. During that time I brewed 1,500 batches of beer, re-pitching the same yeast culture I started with in 1989. I did not re-culture once during that time.

The technique is to run a hot caustic solution in reverse through your heat exchanger followed by a hot rinse. This removes the reddish brown scale that builds up on the plates or tubes. On brew day and after mashing in, I would heat my sparge water up to 200 degrees F and then transfer it from the brew kettle to my fermenter via the heat exchanger, hoses and pumps that would eventually be used to do my heat exchange into the fermenter. Everything that comes into contact with the cooled wort will have been heat sanitized. Assuming you have a clean yeast, you are well on your way to making a clean beer.

The traditional caustic is sodium hydroxide. It works great but it is dangerous stuff. Rubber gloves and eye protection should be used. A good substitute for home brewers is Five Star PBW which is safer. The error most home brewers make is to bypass the cleaning routine thinking that a flush of sanitizer the surface of the scale will do the job on an “unclean” surface. It may sanitize the surface of the scale but will not penetrate to the bacteria laden lower layer. This is why hot water (180 degrees F for 20 minutes minimum) is a better sanitizer since the heat will penetrate. A calcium scale can also build up in the tanks and heat exchangers and an occasional acid wash should be used. Acid is not useful in cleaning out the wort scale which is the prime suspect in harboring the nasty bugs you don’t want in your beer.

Don’t be a skunky monkey. Clean AND sanitize that heat exchanger every time you brew.