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  • Fermenting Room Temperature

    I have 10bbl and 5bbl jacketed fermenters. I am worried about everything getting too cold in the winter here in the mountains for ale fermentation, and I hate turning on the heat, as I tend to be a cheap bastard.

    How low can the ambient temperature of the brewery get before it starts to effect the fermentation cycle of an ale?

    Thanks,
    Dave

  • #2
    I brew ales in an unheated brewery. When we have a really cold winter my fermentation area can get as low as 40+- F. I have not had any problems. Provided you pitch with an active ale yeast and get a good rapid fermentation. It sure doesn't take long to crash though.

    Good luck & Proost,
    david
    Cheers & I'm out!
    David R. Pierce
    NABC & Bank Street Brewhouse
    POB 343
    New Albany, IN 47151

    Comment


    • #3
      The key to this is to ensure that the FVs are adequately insulated. If they are, there should be virtually no limit to low ambient temperatures in winter, or for that matter high ambient temperatures in summer. If the FVs are unlagged, then you will probably not be able to guarantee consistent fermentation temperatures and therefore consistent flavour beers at any time of year. I speak from expereince in the, where our temperatures probably vary far less than where you are based. Generally our vessels are insulated to result in a temperature change of no more than 1 deg C in 24 hours, assuming a temperature difference between the beer and ambient of I think 20 deg C

      Cheers
      dick

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      • #4
        FV insulation

        so starting inside the vessel there should be layers of...

        Beer (or empty space)
        Steel
        Glycol Jacket
        Steel
        Insulation
        Steel

        Otherwise I would think the vessel would sweat in the summer, and get too cold in winter.

        I have an old (circa early 80's) system by JVNW.

        Does all this sound right?
        Dave

        Comment


        • #5
          so starting inside the vessel there should be layers of...

          Beer (or empty space)
          Steel
          Glycol
          Steel
          Chlorine barrier ( to prevent chlorine induced pitting corrosion or corrosion induced stress cracking developing)
          Insulation
          Steel / aluminium / copper / wood cladding


          The use of wood or aluminium instead of external steel cladding is a matter of personal choice, and may be influenced on the degree to which PR is used to influence your profits. The big problem with either wood, copper or aluminium is damage by cleaning materials, particularly caustic. If you do decide to use wood, I also suggest a waterproof membrane (polythene seems to work OK) be installed between the wood and the insulation. It is less essential, but probably worthwhile installing a membrane if using metal.

          Make sure all joints in the cladding sheets are sealed with some sort of flexible mastic to reduce water penetration.
          dick

          Comment


          • #6
            Hi Dave,
            I have the same concern too. My space is currently running at about 40-50F and it's not really even cold here (Pittsburgh, PA) yet. I expect it to be as low as 20F in cold months.

            The upside I'm finding with my first batches is that they are generating a significant amount of their own heat as the yeast feeds. A recent batch shot up from 67F to 84F after the first 20 hours. (A good bit higher than I would have liked.) After knocking the temp down, I've been letting it go on its own, and it's dropping 2-4 degrees/day. I plan to cool it when it bottoms out close to ambient temp.

            So far so good, but I don't know what the cold months will be like.

            Scott

            Comment


            • #7
              My insulated fermenters are in a 40 F room and I notice at the end of fermentation when fermentation slows and therefore less heat is generated, there is a risk of the yeast getting too cold before complete attenuation. I have had good luck setting tank thermostat up during the last third of fermentation when fermentation flavor is less critical and the yeast are able to complete their "Golden Years" as though in Palm Springs.
              Remember that insulation can only slow temperature flow-it can never completely stop it. "Better" insulation just slows more...
              For many years I fermented in my aging cellar with uninsulated tanks by having the tank thermostat turn on/off the room refrig. blower. This was challenging but can be done.

              Comment


              • #8
                Moonlight,
                What kind of time do you like to give your ale yeast to completely attenuate, and can over-pitching facilitate this, maybe shorten the time period? Appart from applying temp control at the start of the ferment when things are getting too warm, I've been letting mine drop down naturally for a few days. I'm thinking about a 14 day cycle from pitch to BBT transfer, and am wondering if it's realistic.

                Thanks,
                S

                Comment


                • #9
                  Fun beer math:

                  Fermentation produces heat. That is why we cool fermenters. Without cooling, fermentation woud get too hot and produce some funky flavors. A cool room will just lower cooling demand during active fermentation. Heat transfer through the side of an insulated tank is less than that produced in active fermentation. Heat loss after active fermantation can be calculated based on the geometry and design of your tank.

                  Each kg of extract that is fermented produces 135.5 kcal or 523 BTU/ degree plato x barrel. (T.Lejsek Brauwelt 1969, 109, 829-833)

                  FYI: British Thermal Unit—A measure of heat energy; the amount needed to raise the temperature of one pound of water by one degree Fahrenheit the specific heat of beer is similar. A barrel of water weighs about 258.7 lbs.

                  Based on your fermentation rate you should be able to calculate the heat produced in fermentation. Delta degrees plato x gallons /h. If I recall this heat exchange through insulated sidewall as commonly found in microbreweries is about 8-10 btu / sq ft per hour (delta T of 40 degrees). q=uA delta T and all that good stuff!

                  MoreBeer

                  Comment


                  • #10
                    I'm not a big fan of overpitching as the longterm health of the yeast should be your greatest concern. Sufficient oxygen and zinc will help keep your yeast viable enough to last thru dessert. Your trusty (but fragile, damn!) hydrometer with temp correction chart will tell you when attenuation is completed. Usually my ales need 2.5 days after they get started. I routinely take a sample and force it (put it in a warmer place the yeast like) to see what the yeast would do if temp weren't an issue. If at 75F the yeast won't drop to gravity beyond what it is in the cooler fermenter, then they have reached attenuation. Your idea of 14 days to Brite is reasonable, but taste it at 21 days before deciding what your customers would like best. I agree with letting the ferm cool by itself when done. Flavor is better and yeast better than crashing-in my opinion.

                    Comment


                    • #11
                      To clarify, I meant 14 or 21 days to be out of your Brite. It is less ideal to have beer sit on the full amount of yeast over, perhaps, 14 days, depending on cooling, condition of yeast in cone, etc. Excess geriatric cells (as would come from overpitching or abuse) are more prone to autolysis, and would necessitate getting the beer off the yeast sooner. Uncrashed beer may give a small desirable amount of yeast into aging which often greatly improves beer flavor.

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