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What is the best way to heat up a bain marie boiler

edited May 2017 in General

I am looking into getting a bain marie boiler and was wondering what is the best way to heat the boiler. I have read about people using steam or oil.

It would be good to understand my options and what people feel is the most cost effective and suitable method to use.



  • The best and most suitable method is not the most cost-efficient method - therein lies the challenge.

    BTW - Steam.

  • edited May 2017

    Who's BM? With respect to our design,,,oil is a pain in the ass to maintenance,kinda spendy, adds to the heat up time, and does not respond well to input adjustments, not a great use of convection. Nothing to do with the design though. Its just an oil thing.

    On the other hand, 12 (45L) or 15 (56L) gallons of water in the reservoir will bring the jacket temps to 250°F (121°C) @ 1 bar very quickly, cost almost nothing, super duper easy to change out/maintain.....Ah steam yes. Our BM design is essentially a self contained steam system,,or can be. Certainly oil can be used if you prefer.

    Need about 35 watts per liter for a two (+ or -) hour heat up time. So roughly 70 watts per liter (+ or -) for a one hour heat up If using oil you'll also need to add the volume of oil to approximate your needed input.

    StillDragon North America - Your StillDragon® Distributor for North America

  • edited May 2017

    Assuming you will be working with grains. Do you plan on mashing and fermenting in the single vessel? If so then using water as a self contained steam jacket is the way to go.

    If you plan on mashing and fermenting in the same vessel and use oil as the heat exchange you will be waiting a LONG time to cool it down.

    Simply add enough water to cover the elements only, the rest of the jacket will fill with steam which is a quicker and more efficient way of transferring the heat. This is how I run my SD BM.

    Using water also has another advantage, you can dump it and then run cool water through the jacket to cool the contents. Once again this is assuming you are a single vessel type distiller.

    Have a squizz at this thread.

  • Thanks guys. I am looking at a double dragon,and it was suggested i looked into the BM. I know steam comes at a cost and you got to have a boiler.

    I don't plan on using one vessel for everything, it would be used primarily for the distilling phase.

  • edited May 2017

    Good point on the cooling ability @lumpany. Just need to be mindful about premature vapor collapse (vacuum) if using a cooling medium that is too cold. Not that big of a deal on the distilling kettles because of the spherical nature of the design.

    But the BM (actual) mash tun would be more susceptible to the affects of cooling too rapidly. Having said that,,the lads at Jackson Hole do indeed use their BM mash tun to also cool their wort with no issues.

    Two way vacuum break/ PRV solves the issue no matter.

    StillDragon North America - Your StillDragon® Distributor for North America

  • @smaug - do the new BM kettles accept wavy elements? What are the limiting dimensions? (length, and top/bottom/side?

  • The element ports remain as 2" ferrules.

    I wanna say the reservoir is 24" deep on yours.

    Should be no problem.

    StillDragon North America - Your StillDragon® Distributor for North America

  • will look into a bunch of these then:


    800 x 800 - 29K
  • Yep. These are the ones that I bought. I was so happy with the first two that I bought another 4.

  • @DonMateo - I got 3 of those, great for clear spirits and my steam generator and OK for well settled beer wash... Now want some 4500's for lower watt density for our molasses wash, had to go with the 1" NPS for the SD EGK, as they did not have those in 4500W... (3 4500's on a 240v 3-phase contactor is cheaper to implement and generates less control panel heat than SSR limiting my 5500W ones...

    On the baine-marie, @smaug -

    24" is 600mm, so assuming this 6kw 480mm triple element from dernord will fit and would be the bees knees..


    I bought one of the 9KW units, but it is 600mm, so might be a tight fit... they make a stainless screw-thread cover instead of the phenolic that I will probably get.. the units have all elements able to be wired independently, so you can use in on single phase or 3-phase, or could wire in series to get really low watt density.. the 9kw(3x 3000w) in series would be 1000w

    800 x 800 - 47K
  • Update, the 9kw 3-phase element above fit in my 1000L BM-A and I have ordered a 2nd one... (free shipping from aliexpress on a single unit, but not on 2)

    I did my first run with 700L in the 1000L and had 3 24" 6kw foldback elements (donated from a brewer friends's 3bbl stout tank system when they upgraded to shiny stainless ones) and it took over 2 hours, so @smaug 's math worked for me... I will add the 2 9kw's for 36kw and maybe 2 more will be 54kw, which should give me acceptable warm up time... That huge power draw will only be for an hour, but it is still huge, and if they switch me to demand metering, I will be getting up much earlier, LOL.. I had to switch to 2 6kw elements (12kw) about the same time as stripping run started with the PRV releasing a bit at 1.1bar, as it should , and we went down to about 10kw during the run... which seems painfully slow....

    Will I get better heat transfer with a higher or lower bain-marie fill level? My thought is that the steam would give more than the hot water, so a lower level would work better... I measured 15 gallons, I think I will put a small valve on the drain endcap and put a piece of clear tubing on it and measure how full it is and take notes of max power I can put in at the same kettle fill with different jacket fills..

  • edited October 2018

    If your are close to popping your relief valve then the temp is constant the whole way thru so probably the water but should be pretty close to same as steam

  • A lower level in the BM jacket works better.

    But the way around the slow heat up and getting up earlier ..... put heat up under automated time and heat up control. e.g .... start heating up at say 05h00 and heat up to say 70 deg C or whatever amount you are comfortable with.

  • @richard said: A lower level in the BM jacket works better.

    But the way around the slow heat up and getting up earlier ..... put heat up under automated time and heat up control. e.g .... start heating up at say 05h00 and heat up to say 70 deg C or whatever amount you are comfortable with.

    That doesn't work if the still isn't full already, then it only takes 15 min to hit the PRV... we are not a 7 or even 5-day a week shop yet... Monday morning is fill the still and start it up, filling it on friday or saturday is not really something I want to do.., I guess I could move it to Tuesday and have fill still and clean fermenters only on Monday...

  • Plus the thermal shock to the steel of pouring cold wash into a blazing hot still.

  • steel? hahahahahaha you heathen's and your steel stills........

  • Doh!!!

    StillDragon North America - Your StillDragon® Distributor for North America

  • Copper like a psycho ex girlfriend, don't even think of even looking at her funny or it ends in disaster.

  • OK, I have 36kw now, the original 3x6kw and added 2 9kw dernord 3-phase elements.. much quicker jacket heat up...

    my 2nd product run on 18kw went real well, and I was able to run 18kw the whole strip, whereas the first one I could not keep 12kw without blowing some off the PRV.. the only difference seems to be the fill level of the jacket... after the last run, the level was just above the bottom edge of the insulation jacket, so it exposed most of the flat, sloped bottom to steam, which gave better/more heat transfer than water and I think the steam can have continual current in the cavity with the steam condensing and being replaced..... Here is the level we will run with tomorrow, marked with a sharpie just above the pattern, an inch higher than we ended last time... I measure by taking out the temp prove and putting in a stainless tube with clear tubing on it, with the PRV removed to vent.


    800 x 600 - 107K
  • That level seems a bit higher than the last one by the amount of power I can put in before hitting the PRV when running.. During warm up, the full 36kw measured over 100Amps on each leg of the 3 phase... During collection, had to cut down to about 16kw this time , ran at 18kw the whole run last time.... We will see what the finishing level of the jacket is tomorrow... Here is a little video..

  • Why would the jacket be any different than starting after one run? Are you losing water through the PRV?

    I run 36kw heating up too. Really the limiting factor much of the time for me is jacket pressure/temperature. If I had more power, I'd just have to cut back shortly into heat-up to avoid over pressure. So heat transfer is extremely important, and thick liquids really need some major agitator action. You probably have it a little easier with just a rum wash, but I've often wondered myself what the optimal ratio of jacket volume is for water & steam in terms of transferring heat from the elements to the inside of the pot.

  • edited December 2018

    @CothermanDistilling Did you come to any conclusion as to the optimal fill level? I now have a system very similar to yours.

  • I think my level detection was messed up, I did not disconnect the PRV, and I think slight suction made the level look lower, after the next run it was right back where it was...

    I think the optimal level is as little as possible without exposing elements... In more practical terms, where no liquid is touching the inner kettle... my bottom is flat and slanted towards the drain, the highest point of the bottom seems to have the most bubbling action during a spirit run where the still charge is clear. I think this is because the lower portion of the bottom has liquid splashing on it, which is conduction, not evaporation, and is lower heat transfer rate i think...

    Does anyone add any kind of boiler additive?

  • IMHO - if you are counting on steam heat transfer, adding additives to raise the boiling point of the water will be counterproductive.

  • additives to keep nasties from growing...
    like this: Outdoor Boiler Stove Anti-Corrosion Chemical Treatment 101 @ Amazon

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