May 07

Backing Out the Therminator

Sometimes process changes aren’t for the better. This fall I made a bunch, starting with the Blichmann Hop Blocker. Then came competition brewing season and I didn’t have time to evaluate the results due to my frantic schedule (1-2 batches a week for three solid months.) The good news, though, is that I’ve now got lots of data both from the NHC feedback and my own testing and I’m going to make some changes.

The verdict? Not good. Several batches suffered from mild wild yeast infections. The judges didn’t always pick up the cause but when you taste them side by side it’s easy to pick up the problem. The other batches seemed to be lacking something that I couldn’t put my finger on. Not one batch was better than what I used to make before.

So, what did I change and what am I backing out? First, I started using the Blichmann Hop Blocker. It’s a great product that really helped prevent trub from reaching the fermenter. The problem, though, was that in the 10 gallon Blichmann Boilermaker my copper immersion chiller no longer fit. So I decided to change over to a Blichmann Therminator. Of course that meant a different setup for whirlpooling and sanitizing at the end of the boil.

Long story short, I tried several methods but ultimately about a quarter of my batches ended up infected in some way or another. The ones that weren’t infected seemed duller. I’m not 100% positive of the mechanism at work but suspect it has to do with letting the wort whirlpool and sit hot at the end of the boil. Why’d I do that? Otherwise the trub in solution at the end of the boil and hop pellet material would clog the Therminator. Ugh, what a mess.

Here were the downsides I found with my use of the Therminator:

  • Infections – despite back-flushing with hot PBW at the end of the brew day, circulating boiling water to sanitize before use, and attempts at autoclaving (which simply took too much effort to do regularly). I hadn’t had a problem with this before and the Therminator was the biggest change I’d made.
  • Added time – all the time I was spending trying to clean and sanitize the Therminator ultimately made my brew sessions longer.
  • Stuck Transfers – on two different hoppy batches I managed to clog up the Therminator completely meaning I couldn’t get all my wort into the fermenter.
  • Leaving the wort hot for longer – compared to an immersion chiller, which started dropping the temp of the whole batch right away, using the Therminator leaves wort at near boiling temp for longer. The Therminator was nice and fast but I had to do a hot whirlpool and let it settle for a total of about ten minutes before I could even start the draining.

Don’t get me wrong. I’m sure some folks are making great beer with this gadget but I’ve given up.

So I’m going back to an immersion chiller with a whirlpool. I’ll be brewing this weekend with this change in place and will post my results. The lesson here for me is to really take a more critical look at any changes I make to see if they’re really an improvement to the end product, the beer in the glass. And I need to do that well before competition brewing season. This year I’m going to use the summer for experimentation with process and I’m going to lock down all changes by October so I have time to let everything shake out before the winter brewing rush.

Happy brewing,

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    • Tom Johnson on June 6, 2012 at 3:21 pm
    • Reply

    How is the immersion cooling going? It’s what I have been doing, but I am always thinking there is a better way.

    Tom J. in Las Cruces (ex-SLOB)

      • Dave on June 6, 2012 at 3:39 pm
      • Reply

      Hi Tom,
      The IC has been flawless. Once again I get great hop aroma, fast chilling, and no infection problems. Unless you had a system too big to use an IC on (or a ridiculously high water rate) I’d stick with a whirlpool IC.

        • Tom Johnson on July 15, 2012 at 5:19 pm
        • Reply

        Thanks Dave, I keep meeting brewers that go back to IC as well.

    • Travis on October 18, 2012 at 8:43 pm
    • Reply

    Hi Dave,
    So you use a whirlpool IC specifically? or do you whirlpool separately? I was curious of how to get a whirlpool when I boil my IC prior to cooling down.

      • Dave on October 19, 2012 at 4:31 am
      • Reply

      I do use a whirlpool IC like the Jamil Zainasheff setup ( It works out pretty well though I don’t get a great cone. I’m thinking of adding a tangential port to my brew pots to make this work a bit better in the future.

    • Travis on October 31, 2012 at 3:39 am
    • Reply

    Thanks Dave. That’s what I was thinking when reading this; Zainasheff’s whirlpool chiller. I heard great things but yes, I too was envisioning tangential ports directly to my brew kettle being more sufficient.

    • Aaron on October 31, 2012 at 1:33 pm
    • Reply

    Dave, I have several years of therminator experience under my belt, and what I have learned is that some sort of filter( hopback, trub filter, hob bag, etc ) after the kettle is key towards keeping your chiller free of unwanted guests. I’ve had great success with using an asparagus steamer type hopback, as well as upgrading to the Blichmann HopRocket between the pump and chiller. When I switched to installing the hoprocket after the pump, I noticed I was getting greater amounts of fine hop leave parts stuck in the chiller. My solution for this was the BrewersHardware “trubfilter”. For cleaning, I do a 10 min flush with boiling water via the pump while the wort is whirlpooling. After the wort is in the fermenter, I back flush for 10 min via boiling water and the pump. Every 5-7 brews I back flush/recirculate boiling solution of b-brite, followed by water to rinse. I recently have also started to store everclear in the chiller when I know it will be a few months between brews.

      • Dave on October 31, 2012 at 4:44 pm
      • Reply

      A good trick I heard from a friend was just putting the Therminator in the hot liquor tank during the mash. That pasteurizes it for 60 minutes at about 180 F.

    • Nick on February 11, 2014 at 3:09 am
    • Reply

    You stated in the article that, “Im not 100% positive of the mechanism at work but suspect it has to do with letting the wort whirlpool and sit hot at the end of the boil.” I was thinking maybe an easy solution for this would be to begin chilling through the therminator while you are still boiling. And maybe consider the use of a hopstopper.
    Don’t the big brewers use something like a therminator as well? If hop aromas and flavors were such a big concern I’m sure they would be the first to use immersion chiller’s.

      • Dave on February 12, 2014 at 8:05 am
      • Reply

      Hi Nick,
      Thanks for your comment. Were you thinking of recirculating to start chilling the whole batch? I’ve heard of people doing that and it’s certainly an option. I would be concerned that doing so would run even more trub through the chiller and cause even more clogging, though. I’ve tried using a hopstopper but those can clog pretty easily with pellet hops and when that happens and the wort is still boiling it’s pretty tough to fix. It would probably work with whole hops, though.

      Big brewers use a plate heat exchanger. There are multiple layers and they usually run hot caustic through the heat exchanger on a regular basis to keep it clean. The passageways in the heat exchanger aren’t nearly as small as in the therminator so they’re not as likely to get plugged up. Additionally they’re able to disassemble the heat exchanger and clean the insides.

      I don’t think the comparison for what big brewers does applies here since the volumes and surface area are so different between a commercial brewer and a home brewer. Additionally the cost and mechanics of dropping in a giant immersion chiller just about rule it out. Instead they often whirlpool and add hops at that point. That’s something that could certainly be experimented with but ultimately the point of my article is that with all these adjustments, problems, and hassles I didn’t see nearly enough benefits to stick with the Therminator.

        • Nick on February 13, 2014 at 3:00 am
        • Reply

        I didn’t mean to recirculate. What I was thinking is that you could just gravity feed your wort to the therminator while it is still boiling. That way your wort isn’t just sitting there at the end of the boil, because you never stopped boiling at all. You could control the flame as your wort drains down so you don’t scorch it.
        I was thinking about buying a therminator but now I am on the fence after I have been coming across all these stories about low hop aroma/flavor issues. I just thought maybe this would be an easy solution.

          • Dave on February 14, 2014 at 6:12 am
          • Reply

          Hi Nick,
          You could certainly experiment to get the Therminator working but what I realized was that I was spending a lot of time and effort on using it when I had yet to see it improve my beer. If you have a process that demands you use a heat exchanger (e.g. very large boils) then by all means put in the effort to get it working. Otherwise, I’d simply advise that it may not be worth the hassle.

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