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Tank Heaters

This is just a comment. I remember reading somewhere for tank heating for fermenters some people use fish tank heaters and I bought a couple. Cold snap this morning, it was 2°C and my garage is open so I put in the 200W tank heater in the 200L water tank. Six hours later the tank went from 10°C to 30°C and lots of happy yeast. So the system works.


  • We had a cold snap here last night. My fermenters dropped from 29.5°C to 28.7°C.

    Real brutal winters here in Fiji.

  • Ferment larger volumes and you won’t have to worry about getting too cool. Higher the volume, the less surface area, the less passive cooling.

  • I'm wondering where the fermenter volume watershed will be between heating and cooling a larger fermenter. I notice that Zottel produce open topped fermenters with a cooling jacket welded to the top of a 1100L vessel for example. Since my 100L rum ferments of rum in the UK require heating (to maintain a temp in the 30's), I'm unsure if 1000 to 1100L will be a large enough volume to flip it to a cooling requirement. If not, the jacket will be in the wrong place to efficiently pump warm water around for heating purposes. My fermentation building varies from 10 to 20 degC winter to summer. I'd be grateful if anyone could give me a steer about whether I'm worrying for nothing!

  • I've just found this comment on another thread by grim: "50g/150l is about the point where cooling begins to be required, especially if you have warmer/hot ambient temperatures. As surface area to volume declines, tanks will tend to heat. Under that 50g/150l mark, you likely run into the need to heat, get up to the big tanks (2000l), and it's the opposite"

    So I guess at 1100L I won't know if I need to heat or cool, but it won't be much either way. Perhaps I'll have to look at 2000L to be sure of the answer!

  • The manufacturer may be able to answer that.

    StillDragon Australia & New Zealand - Your StillDragon® Distributor for Australia & New Zealand

  • edited July 2019

    The only time we ever see fermenter temperatures cool earlier than we'd like is when our internal temps are around 55f/13c in the dead of winter, and we're purposely running slow funky rum ferments (10-14 days). This is on 2000l/530g fermenter volumes.

    Right now, we are running two faster dark rum ferments, 1080 gallons across the two fermenters. Our 3 ton fermenter chiller is running pretty much non-stop on day 2-3.

    Without chillers, the fermenters will very easily spike past 95f, regardless of the starting or ambient temperature once vigorous fermentation begins.

    We like to keep rum at 82f/27-28c. It's about 85f/30c indoors.

  • edited August 2019

    @grim said: dead of winter, and we're purposely running slow funky rum ferments (10-14 days).

    Sounds,,,,,well I don't know how it sounds? But it doesn't sound like rum country lol. Ya gotta do what ya gotta do.

    StillDragon North America - Your StillDragon® Distributor for North America

  • Arroyo said Winter rum is the best rum

  • Ah winter. Yes, An Arroyo winter lol.

    StillDragon North America - Your StillDragon® Distributor for North America

  • edited August 2019

    Brilliant stuff in here, can dissect this for days...

    The Aroma Of Rum III (Influence of Fermentation Technique), Rafael Arroyo, 1940 @ Boston Apothecary

    Every rum distiller knows the effects produced by the more or less elevated temperature in his fermenters in terms of fermentation efficiency and yields; but few have thought about how the degree of temperature influences the fermentation in terms of quality and aromatic intensity of the finished product.

    As a first point, the factor that has the most influence on the speed of fermentation is that of temperature. Within the limits acceptable as healthy practice, we will find that the higher the temperature, the greater the corresponding fermentation speed. We have already indicated that for the development of fine bouquet the fermentation must be slow rather than fast; then it is necessary that the distiller try to conserve the optimum temperature for formation of the desirable aroma.

    Our experiments in this regard have indicated that relatively high temperatures (between 35°-38° C.) in the fermenters lead to undesirable bouquet in the finished product. And for these two important reasons, among many others: (a) the formation of undesirable metabolic products, of many penetrating odors; but always little aromatic; (b) the tremendous increase recorded in the autolysis of the yeast, with consequent bad odors during the period of the distillation. On the other hand fermentation temperatures between 27° and 30° C. lead to the development of fine aroma in the distillate. This is because other conditions remaining equal and constant, we will obtain better distillates in winter time than during the summer; and at all times, better distillates at considerable height above sea level than near the coast….

    In the practice of rum manufacturing, this is the factor that offers the most difficulties for its control, since our climate does not lend itself to getting temperatures between 27° and 30° C. in the fermenters for most of the year. And even in those distilleries where the fermenters are equipped with devices for artificial cooling of the batición by circulation of water in the interior, or application of water on the walls of the fermenters, we often find that the difference in temperature between water and the batición is not large enough to exert any practical benefit. This happens, of course, during the hottest time of the year. As we pointed out above, distilleries located at considerable height above sea level have a great advantage in this regard.

  • @grim. This is great. Actually this discussion is making me want to try and make some rum. Where I live is at 900m elevation and in March and September the ambient air temperature is about spot on 20 deg C. I would assume this applies to whiskey. The reason why I ask is that my lastest 6 whiskeys are just aging out in 50l barrels, And I did most of them in March but they have been in the sun for a couple of hours during the day so they are aging pretty fast. Anyway I tried three of them yesterday, my quinoa whiskey, an Irish and a straight wheat, I thought they were really good with great aroma, surprisingly so given their age. And I remembered that for most of these ferments I let them run about 7 days. Where as the ferments I did in Nov through Jan all feremented out in 4 days, as it was bloody hot. Actually I lost about 4 due to the temps going over 35 deg with my the tanks I had in teh sun.
    So does a slower fermentation producing better flavors apply to whiskey as well??
    I am using EC1118 as my yeast for all my ferments. I dont have a run yeast but I will get some soon.

  • Thanks for posting. I think you've posted that before no?

    Yeah I'm just ribbing ya from "the garage" is all. Best ferments are definitely in cooler weather. Best dunder pits are in the warmer weather has been my experience here in FL.

    Kinda like life. The best bits are spread out over time and never seem to come together at the same time.

    StillDragon North America - Your StillDragon® Distributor for North America

  • lots of great reading in that boston Apothacary site.

    @DonMateo IMO malt whisky needs a coolish temperature to ferment out at ie around 20-25C especially if you are using beer yeasts as above that the yeast starts getting stressed and introducing off flavours.

    The yeast strain chosen will dictate the temp eg the spec sheet for safspirit m1 states "Optimum 20°C – 32°C (68.0°F – 89.6°F). This yeast may ferment at lower temperatures with slower kinetics. At higher temperatures, this yeast may ferment with lower alcohol yields"

    The specs for safspirit D53 states "optimum 30 °C to 32 °C " It's described as "Able to give a large variety of flavors such as white fruits (apple, pear, peach) or exotic fruits (banana, mango), this yeast is ideal for distillers wishing to produce tasty malt new-make spirits." My bet is the temperature will impact which of those flavours is produced

  • edited August 2019

    @Smaug - No this is new stuff, before Boston posted this, it was probably lost for decades. One paper that’s part of a series that’s far more significant than the heavy rum patent.

  • @grim and @crozdog, thanks very much. I have downloaded most of the boston apothacrys site and I need to do some more reading so it seems. All this makes sense I think in Nov and Dec I was stressing the shit out of my poor yeasties as it was too hot where they were.

  • Rum ferments here in Florida between 80F and 86F are a fairy tale without some sort of cooling. Or just do them during December and January.


  • I love my recirc cooling from the bottom, through a SD 2" Long PC, back in to the top... the constant recirc of the yeast keeps the fermentation going in the end, and uses the bottom of the fermenter as a temperature ballast for the top, if you monitor even with just your hand, the top is much warmer than the middle without circulation..

    Then run a small pump through the SD PC a heat exchanger(radiator/fan) an/or just a tote of water in a cooler spot... for the wash pump, up to 200L can be the simple $20 tan homebrew pump, up to 1000L the 'MkII' style pump works great..

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