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Heating fluid for Bain Marie
Hi I’m looking for recommendations for heating fluid to be used in a Bain Marie still. So far I’ve looked at vegetable oil, ethylene glycol, and commercial heating fluid. It appears to me that the different selections i have will have a varying life spans.
The jacket and pot are stainless and it looks to hold around 15 gallons. The elements are 5500 watts each and there are 4 of them.
I would prefer to have a long lifespan of the fluid and of course be food grade.
For those wondering the commercial fluid i looked at is $200 a 5 gallon pail. I’m ok with spending the money but if there’s a cheaper option I’d sure like to know what you guys are using and what kind of lifespan your getting from it.
ND
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3 Replies
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I looked into this myself. The thermal transfer oil was quite expensive. Ended up just using distilled water. While heat transfer fluids can attain a much higher temperature, I like water because it will never scorch whatever I have in the still so I can do grappa, etc. with no concerns. I can’t do that on our larger still with a steam jacket because it will scorch. I like the gentle heat for the small still.
For our pilot still, the heating elements are so cheap, I don’t really care if I go through them every few years if water ends up being harder on them (not sure that it is though as I’ve only had to replace one when it shorted out).
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I agree with @jocko water is the way to go, just one thing to make sure of is to check what pressure your jacket is rated for.
Typically if its good for 15 PSI or more you are good to run a closed jacket with a pressure gauge and a relief valve and essentially have low pressure steam heating in the jacket. DO NOT RUN A CLOSED JACKET WITHOUT A PRESSURE RELIEF VALVE. This is how people get injured. Also a Vacuum relief is a good thing to add to the system too.
Otherwise run with the jacket open to the atmosphere. It wont be as efficient, but it is safe.
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I run a water jacket. Here’s the advice I received from StillDragon:
– You can use any water, but replace it every 2-3 weeks if you’re using it daily. The heat from the elements can cause some breakdown of the water and chemicals in it, and that can cause damage to the interior of the jacket. How much who knows, but I just do the maintenance to minimize it.
– Set the level of the water just below the bottom of the kettle so they are not touching. You want to use steam heat. The water will be colder. If you’re using a still not designed to generate steam this might be difficult.
– The first time you use it after changing the water keep it open to the atmosphere until you get steam, then shut the valve. You want to minimize regular air in it. It messes up the thermal conductivity of water alone.
– As stated above, use a PRV that also does vacuum relief. This works as both a pressure relief valve at 15psi, or a vacuum break at any vacuum: https://shop.stilldragon.com/1-bar-stainless-steel-pressure-relief-valve.html
– If you’re doing this with pressure the jacket will reach temps in the 220s+. Kinda perfect for running high solids washes. We do high solid washes and have never had an issue with scorching. It’s hot enough to go through the tails but not enough to do bad things.
I have three 5500w elements in the 50g still and I can just barely hit 15 psi at 15 amps @ 220v (each). I tend not to go higher than that as I like to take it easy on the controllers and wiring.
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