Double Boiler (Bain Marie) Efficiency

[Represto]

As I contemplate my next boiler, I'm thinking that a double walled (bain marie) might give me a lot of flexibility. While I do like to make grain mashes that don't require a double boiler, I also like to make fruit spirits. A double boiler would make like so much easier for the fruit mashes - especially with electric heating.

My question is there much of a trade of in efficiency with a double boiler? Do they add a lot of time and effort overhead? Does it take much more time to bring a charge up to boil?

[shadylane]

Here's the big questions
What are you going to use for heat transfer fluid ?
Is the jacket on the Bain Marie going to be pressurized ?

[Represto]

I'm going to go ahead and retract my question. The more I jump into this rabbit hole the more I've decided I don't want to be in it. While I might go double walled at some point, I'd rather focus on....everything else other than the worries that going along with it. I'll just spend the time on filtering and clearing rather than worrying if my hobby pressurized still is going to blow up with hot glycol!

I'll leave the double boiler for the next progression of this hobby.

[vqstatesman]

I purchased myself a 150 litre brain marie with agitator. The jacket is rated at 15 PSI and I use it as a self contained steam jacket.

It's one of the BEST toys I have EVER purchased!

If you're still interested Im happy to talk numbers and efficiency.

[Kareltje]

I would like to see the numbers and equipment.

But to suggest another solution: I am very happy with my thumper. I have a boiler and thumper of 1he same size and I never have to filter or sieve again. When there is not enough juice in the mash, I fill the boiler with water and run it like a steamstill. Never scorches!

[Represto]

Ya, I'd love to hear about the 150L bain marie. Did you have a single-walled boiler prior? If you can give your impressions of efficiency compared to single-walled that would be awesome. Also interested in the pain-in-the-ass factor of running the steam jacket.

Do you have a link to the unit you are using? Or something similar?

[vqstatesman]

Ya, I'd love to hear about the 150L bain marie. Did you have a single-walled boiler prior? If you can give your impressions of efficiency compared to single-walled that would be awesome. Also interested in the pain-in-the-ass factor of running the steam jacket.

Do you have a link to the unit you are using? Or something similar?

Yes I previously had a single wall 50 "milk can" boiler with 2 * 2400 immersion elements. Can't remember exactly how long it took to warm up but think it was appropriately 60 mins with full power.

My current 150 litre BM has 3 * 3600 watt elements in the jacket. The jacket is only filled with enough water to cover the elements, this creates pressurised steam which heats the boiler contents with no scorching at all. Anything can go in the boiler without ANY scorching. I do have an agitator which probably aids in reducing scorching. The jacket is designed to run up to 15 PSI and has the necessary safety receive valves etc. It takes approx 80-90 minutes to bring to the boil with approx 9000 watts being fed to the 3 elements.

Once the column starts producing product I cut power to about 5000 watts on average. My 4 inch 4 plate with pro caps cranks out 85 average ABV at approx 6 hours per litre from a mash/wash of 10% ABV. Single runs for me.

Here is a couple of links I have shared previously viewtopic.php?f=88&t=63651 and https://www.stilldragon.org/discussion/ ... ler#latest

Let me know if you have any other questions. Ohh and did I say I highly recommend a BM setup? worth every single dollar spent.

[Represto]

Whoa! That's a beauty. So, you ferment in the boiler as well? Do you do any racking or do you run it with grains and everything still in the boiler?? I hadn't even considered that as an option.

I'm assuming there were 5 digits on the price of that set up. 150L is too big for my uses right now - nor would I have space for the pot belly. I'd be looking at a 100L milk can. I could still add an extra triclamp port at the top to mount an agitator. Can you think of any gotchas or suggestions for going with a milkcan BM setup based on your experiences?

[Represto]

https://www.northstills.com/product/100 ... el-boiler/

Looking at this boiler. I just don't quite understand how it works. The jacket if filled with water or oil and it's heated with the electric element - got it - but it's vented, not pressurized. How does the water in the jacket not just boil dry? Does this just billow steam?

[still_stirrin]

...The jacket if filled with water or oil and it's heated with the electric element - got it - but it's vented, not pressurized. How does the water in the jacket not just boil dry? Does this just billow steam?

Make up water? Is there a level gage in the jacket? Add water as needed to maintain a level.

Remember, boiling water is hotter than you need to boil your wash. But, you need the heat input to maintain the wash boiling.

Also, heat transfer rate is improved when the temperature difference between the jacket fluid and the wash is increased. So, if you can maintain a slight pressure in the jacket, you can get the temperature difference wider, improving the heat transfer to the wash. Even 5 psi is an improvement and steam at 15 psi is saturated at approximately 250*F.
ss

[DAD300]

I have ban marie still. It has a Pressure Releif Valve set for 5psi on the jacket and on the boiler. It also has a Swinging Gate Valve as a Vacuum Relief Valve, so it won't collapse itself on cool down.

I fill the jacket approx half with water. This setup allows steam to fill the upper half of the jacket.

Run at 3PSI during heatup, allows the jacket temp to get to slightly above boiling, approx 225F. I figure about 85% efficiency.

So, I can heatup as quickly as an immersion heater if I want to, but use about 15% more power to do so. The efficiency gets better during the run, but I haven't calculated that.

Distilling with the grain in does change the flavor. Seems to carry over more flavor and sweeter.

[Represto]

Found this site that explains it very well.

http://distillique.co.za/distilling_sho ... ket-boiler

TL;DR: Add water to the jacket enough to cover the heating element + a bit. The water will heat, turn to steam, and then condense back to liquid. This process is more efficient than filling the jacket. Since the steam condenses, it doesn't actually vend off much steam and shouldn't require top ups during the distillation process.

Additionally, there's mention of using a 'steam wand' immersed into the boiler to increase efficiency. I need to research it more but these two things seem to contradict with each other. If the steam will condense back into the jacket and not vent off, how would a steam wand work?

[Kareltje]

That is really usefull information!

[vqstatesman]

Yes I ferment and distill in the one vessel. I do not rack off or remove the yeast. Think about what the big boys do, they do not remove yeast. In my opinion the yeast improves mouth feel etc, but that a whole other debate.

In terms of cost my BM setup was approx $7-$8K AUD. With all the bells and whistles including an electrican to wire up new outlets not far off $10K AUD.

Jackets are great and have the added benefit of being emptied and run cold water if I need to cool my mash down.

I can not comment but I would have though no pressure or low pressure would take a lot longer. I tend to run my jacket between 10-15 PSI during warmup. If the jacket is not pressurised or low PSI you could run oil.

[Represto]

Interesting. How essential do you feel the agitator is to the success you've found with your setup? How firmly would you recommend an agitator for a 100L jacketed setup?

[vqstatesman]

Interesting. How essential do you feel the agitator is to the success you've found with your setup? How firmly would you recommend an agitator for a 100L jacketed setup?

My passion and goal is to make bourbon. Therefore the agitator is a must, considering I use the single vessel for mashing too.

My agitator is relatively heavy duty as is my whole setup. The agitator drives the price up massively as the walls all need to be thicker grade of steel. I probably could have saved a good 30% of $$ if I dropped the agitator, don't quote me on the maths as agitator was never out of the question. To put things into perspective my boiler weights approx 150KG, thats empty and with no column.

If you are not mashing I don't think the agitator is a must. However the agitator does help to distribute the heat from the jacket on warm up and means you can throw more power at the jacket.

All depends on your needs but by nature I think a BM would still work great with an agitator.

I'm just a hobbyist and certainly still learning lots. I'm not wealthy but not tight on money either. I'm very picky and often critical however my boiler is one of the best toys I have ever bought.

[Represto]

Reading through some other posts, some have expressed concern with stacking the plates in a flute setup with a BM / jacketed boiler setup.

I've since sourced out a 100L/26G low pressurized (5 psi) boiler with an agitator and a 3" 4-plate flute heated with a 5500w electric element. The price is right, the size is good, and I'm hoping that it will allow me to mash-ferment-distill to finish product in one go. No racking, no stripping/spirit runs. I'm not looking to do a neutral and will mostly be running bourbon and fruit mashes.

@vqstatesman and @dad300 are you doing one and done with your setups? Do you have issues stacking plates? Thoughts or concerns on my proposed setup?

[vqstatesman]

Reading through some other posts, some have expressed concern with stacking the plates in a flute setup with a BM / jacketed boiler setup.

I've since sourced out a 100L/26G low pressurized (5 psi) boiler with an agitator and a 3" 4-plate flute heated with a 5500w electric element. The price is right, the size is good, and I'm hoping that it will allow me to mash-ferment-distill to finish product in one go. No racking, no stripping/spirit runs. I'm not looking to do a neutral and will mostly be running bourbon and fruit mashes.

@vqstatesman and @dad300 are you doing one and done with your setups? Do you have issues stacking plates? Thoughts or concerns on my proposed setup?

One and done for me. I have no problems or issues with stacking the plates. No difference between a BM and any other boiler.

If you are worried about pressure in the boiler. It’s no different to any other boiler. You can have a relief valve on the boiler. A relief valve on the jacket is a MUST.

[shadylane]

When using a steam wand like this
http://distillique.co.za/distilling_sho ... g-to-boils
The mash is slowly being diluted with condenced steam.
Stacking plates or a packed column ontop will exasterbate the problem

[Represto]

Thanks, vqstatesman. Very good to hear.

Shadylane, I'm going to hold off on the steam wand for now but I'll report back in the future if I go that route - noting any related impact.

[amdamgraham]

I have a non-pressurized BM with a 1500 watt element. I typically fill the outer boiler with about 5-6 gallons of water completely submerging the element and the water level reaches about 75% up the sides of the inner boiler once it is in place. The inner boiler has a capacity of 7.5 gallons but I make 6 gallon all grain whiskey batches (6 gal + grain volume) and distill on-grain. I don't ferment in the same vessel because it's not practical in my situation. It does take some time to get going though. I fill the outer boiler with hot tap water and plug it in and it typically takes three hours to start producing, then about another 2.5 - 3 hours before I shut it down. It makes for a very long day when you factor in clean-up. From the thread above I am starting to think that I am over-filling the outer boiler. Would using substantially less water speed up my runs? I understand that less water needs less power to get up to temp but does the steam produced work better than direct water contact against the inner boiler?

[Represto]

Interesting. Thanks for sharing. Are your outer and inner separate pieces? Or does your boiler have a vented jacket?

[Samyguy]

steam will transfer BTUs/heat faster as it condenses than liquid water inside you unit.

[amdamgraham]

The design was based on the design provided in the book, "Moonshine" by Matthew Rowley. The inner/outer boiler are two separate pieces. We did adjust the size just a bit to give it more volume (my brother is great at math), I think the column head is a little taller and we also bent the copper such that it hooked together at the seams (that takes a ridiculous amount of patience in bending copper like that so you don't break it) and soldered, no rivets. We were tracking temperatures using a PC and probes at the inner boiler, outer boiler and top of head and it was fun initially looking at the graphs but I never tried variable levels of water in the outer boiler before the PC died. Now I just cork those port holes and run it and save lots of little jars. If by some bizarre chance there is a blockage anywhere in the system a cork will just pop out...