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Wild Fermentation

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  • Wild Fermentation

    Anyone off hand have any ideas what will ferment at around 36ºF and produces a strong sour milk smell?

  • #2
    Think you could have a powerful entero species doing its thing?

    What is your pH and estimated ABV?


    • #3
      I don't think anything grows particularly fast at 36F. However, Pediococcus, some lactobacilli and possibly zymomonas will grow over a period of time and produce sour taste and hazes. Less likely would be some wild yeasts. Whatever it is, it shouldn't be there!

      A major brewery clean up operation is required whatever the cause is, along with fresh yeast from offsite (and I suggest a new source if you are getting wet yeast from another brewery, as it may have come in with their yeast).


      • #4
        Thanks for helping out guys.

        Sorry for not giving more info, but I'm entirely too busy at the brewery and the short time I have at home. Since I seem to be the only person at the brewery truly interested in figuring out what exactly happened no diagnoses has happened, and I haven't had time to really dig into this. I suggested doing a lot of things, but all that has been done is tasting. The standard ABV for this beer is 5.1%.

        So here's the situation:
        One of our filtered canned beers, a blonde ale, got transferred to one of our smaller brites after a canning run because we needed the 40 bbl brite it was in for another beer.
        It was about 12 bbl pushed with CO2 into a smaller tank with about 10 bbl of headspace (I was not the person that did the transfer).
        It was in there almost two weeks, I think.
        The tank was set at 36ºF.
        I went to go can it this past week and I noticed the strong sour milk aroma when I blew off a little CO2 from the blowoff tube.
        Unlike anyone else before me, I taste the beer in the tank -- and out of the canner -- before packaging.
        It tasted a bit more neutral with possible acidity (I was second guessing it could be mental after suspecting an infection).
        I tasted it against the last batch still on tap in the taproom--certainly a little different, but nothing new for us because our beers are always a little different (starting to see a trend?)
        Since it didn't taste bad, I was told not to worry about it and run it. I didn't feel good about this.
        I went to blow the tank down after the run to have a look inside -- although because it was a filtered beer, we normally clean under pressure -- as soon as I opened the manway door, there was krausen-like foam up to the bottom on the manway.
        After the CO2 dissipated, I looked inside with a flashlight and saw a small krausen line around the 12 bbl level.

        I'll spare you the rest. I'd like to say I'll try to do that tomorrow, but I'm sure I'll get roped into do most of a ~12,000 can run plus everything else that needs to get done that usually doesn't unless I do it. I'm also flying out of town Tuesday, so it may be another week before I get any more important clues as to what we're dealing with.

        Hopefully with the very recent installation of a very expensive date coder, I'll be more successful with lobbying for a lot more quality control measures...because what good does it do otherwise if we can't get our collective acts together around the brewery.