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Thread: conical temp variations and lager yeast

  1. #1
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    conical temp variations and lager yeast

    so we have two thermowells on our 4bbl conicals, one in the lower area of the cone and one at the upper edge of the cone. the lager yeasts we use will throw up a good size krauzen, so i assumed this was the spot with the most activity and put the probe in the upper thermowell. (we've been doing 2-2.5bbl batches while we work out the kinks)

    after a few very slow starts and some gravity samples that were a good 3-5 degrees lower than the probe reading, im wondering if i should reverse course and use the lower thermowell that's closer to the cone bottom for the temp probe.

    i know that "bottom fermenting" isnt a true depiction of lager yeast, as evidenced by nice big krauzen heads. but our strains do tend to floc pretty well, so im wondering if more of the activity is happening closer to the cone bottom where the floccs settle? should i be more concerned with getting a good reading of whats down in the cone? worry less about the floaters in the krauzen?

  2. #2
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    bump. anyone?

  3. #3
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    Calibrated Thermometer

    Stupid starting point -- have you checked that the thermometer is reading accurately?

  4. #4
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    Quote Originally Posted by MoonBrews View Post
    Stupid starting point -- have you checked that the thermometer is reading accurately?
    Yes, check this for sure! And if they are reading accurately (or even close), it sounds like the real problem is temperature stratification, probably because you're only using the cone jacket due to the small batch size. Just a wild guess. But moving the thermometer position won't change that. If it's mostly covered, maybe you can run just the top jacket. Or does the vessel have only one jacket?

    Regards,
    Mike Sharp

  5. #5
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    Quote Originally Posted by rdcpro View Post
    Yes, check this for sure! And if they are reading accurately (or even close), it sounds like the real problem is temperature stratification, probably because you're only using the cone jacket due to the small batch size. Just a wild guess. But moving the thermometer position won't change that. If it's mostly covered, maybe you can run just the top jacket. Or does the vessel have only one jacket?

    Regards,
    Mike Sharp
    No, i havent had a chance to calibrate the probes recently. (i'm in NoCal, nano is down in Baja) I picked up a few spare probes in case there are issues with the existing probes. Will be down there this weekend.

    The FV has two jackets, cone and upper. There's little to no contact with beer on the upper jacket. Why would i run that and not the cone?

  6. #6
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    We have had a strange time with Lager yeast. As we crash it slowly and the yeast begins to floc, it flocs so slow that it covers the well and they no longer read correct temps. We end up with 28 degree Lager. So far no problems other than that. I have JVNW 60 bbl tanks with 3 thermawells each.
    Joel Halbleib
    COO / Zymurgist
    Goodwood Brewing Co
    636 East Main St
    Louisville, KY
    goodwood.beer

  7. #7
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    Quote Originally Posted by brain medicine View Post
    No, i havent had a chance to calibrate the probes recently. (i'm in NoCal, nano is down in Baja) I picked up a few spare probes in case there are issues with the existing probes. Will be down there this weekend.

    The FV has two jackets, cone and upper. There's little to no contact with beer on the upper jacket. Why would i run that and not the cone?
    Well in this case, obviously you wouldn't. But you could still be getting stratification. If the probes end up reading relatively close to one another, what else could it be? I guess you have to pick your poison, so to speak. Control on the lower temp in lower position probe in the cone, or control on the higher temp in the higher position probe. Or recirculate, which might be ok on a temporary basis while you dial in your process. I think once you can get the top jacket covered and chill with that and not the cone jacket, this problem will go away.

    Regards,
    Mike Sharp

  8. #8
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    i'd be pretty hesitant to turn off the cone cooling, i'd think the yeast that has flocc'd to the bottom but is still active and is resting on top of trub in a cake would generate quite a bit of heat all bunched up together. i feel like i've read /seen countless references to yeast as great insulator and retaining alot of heat, etc.

    unfortunately recirc isnt really an option as our racking arms are fixed pointing down, not much movement gets generated. and not a permanent solution either.

    im hoping that i can dial in our HX and cooling systems this trip, and then start to do double batches to fill the tanks. maybe the extra vertical height will generate some movement and circulate the wort?


    on a kind of related note- the temp probes are two wire, resistive type. if i connected their bare leads together at the temp controller would it simply average the two readings? i assume the controller would read the resistance from all of the wiring in the whole circuit, i.e. both probes. anybody know if i'm off base here?

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