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  • Cross contaminated yeast strain

    Anyone having issues with yeast from White Labs? We seem to be having issues with a lager strain exhibiting hefeweizen-type flavors after a few generations. Believe it to be a Saccharomyces type cross contamination.

  • #2
    You can send some beer out for testing, pretty sure white labs will do it for you. Do you use a hefe yeast in house? I would bet that the source would be most likely from internal sources ie: improperly cleaned brink or fermenter. White Labs is pretty good at not having contaminated yeast. The other possibility is that your lager yeast harvesting procedures are artificially selecting for mutated yeasts that have that character to them. It can happen, usually it shows by going from a less flocculent yeast to more flocculent, but it can go the other way too.

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    • #3
      I had this issue once a few years ago with White Labs. It was very faint in the original pitch and dominated in the second batch. I let them know about it, they sent me a new batch, and I call the contaminated batch something else and people drank it. I also sent a sample to them for analysis and they said it was not contaminated with something other than yeast. My contamination seemed to be Belgian in nature, but hefe is close.

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      • #4
        cue deje-vu feeling

        Originally posted by Jim Lieb View Post
        I had this issue once a few years ago with White Labs. It was very faint in the original pitch and dominated in the second batch. I let them know about it, they sent me a new batch, and I call the contaminated batch something else and people drank it. I also sent a sample to them for analysis and they said it was not contaminated with something other than yeast. My contamination seemed to be Belgian in nature, but hefe is close.
        Would you happen to remember what specific strain you had issues with, and also the style of beer? Do you know if you were also using any Belgian strains at the time?

        I ask because this sounds very familiar to some recent observations...

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        • #5
          It was WLP820 in a traditional lager. We do have belgian strains in house but tracing back the tanks/CIPs/location of hefe strains, nothing is lining up for me to have an in-house cross contamination. I've purchased about 3 lager props from white labs in the past 6 months and all of them have shown phenolic, ester, bubble gum off notes after a few generations. I sent samples to an outside and it came with a cross contamination of two Sacc. strains. We have another lager strain in-house from Wyeast and the batches that have used this strain have never come back with these off-flavors.

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          • #6
            Eerily similar to what we are experiencing.

            All signs point to in-house cross contamination for us, but I'm still not convinced the problem isn't in our fresh pitches to start with; It's way too hit-or-miss with batches that show issues vs batches that do not.

            We have had a lot of issues with one specific beer, that was dumped (twice) after being fed a 2nd generation pitch. We're trying this recipe with a fresh 1st gen pitch of 007. I almost want to save some slurry and send it out for contamination testing from this 1st gen.

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