Experiment: Sanding the inside of a still to increase nucleation sites

Now that I have a still with an observation window I noticed that it only boils in a small number of spots. I'm hoping to create to create a more even boil. The inside of the still is polished stainless steel. I noticed that the areas that bubbled were directly over the heating elements or a couple other spots that had flaws. So as an experiment I gently sanded a small area of the still with 120 grit sandpaper. The area does not bubble during operation and is away from other areas that do. I didn't want to go too crazy with the grit as I still want it easy to clean. But if the 120 doesn't work I will try 80, then 40. With each grit I will do a different area and see how each one works. Once I find one that does a good job I will sand the entire bottom surface of the still. I may or may not do the sides.

Once I do a few runs I will report back.

Nucleation @ Wikipedia

Nucleation in boiling can occur in the bulk liquid if the pressure is reduced so that the liquid becomes superheated with respect to the pressure-dependent boiling point. More often, nucleation occurs on the heating surface, at nucleation sites. Typically, nucleation sites are tiny crevices where free gas-liquid surface is maintained or spots on the heating surface with lower wetting properties. Substantial superheating of a liquid can be achieved after the liquid is de-gassed and if the heating surfaces are clean, smooth and made of materials well wetted by the liquid.

Superheating is what I want to avoid. I want a nice even boil at consistent temps. With superheating you can get surge boiling which is uncontrolled and inconsistent. I'm hoping that also will help with separation of the factions. It may also help with increase the speed of production too though maybe not that much?


  • Save yourself a stack of work and put some marbles in there or something.

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  • Ceramic saddles, stainless scrubbies slipped over the heating elements, sand, a handful of stainless screws.

    Like punkin says, these all add plenty of nucleation sites without resorting to scuffing your kettle.

    Surface roughness might make cleaning more difficult.

  • Also - variations in column backpressure (increases and decreases in liquid level on plates) will vary the kettle pressure, and subsequently impact the boiling temperature.

    I've seen kettle boiling go so far as to oscillate based on the backpressure of tall columns.

  • Snap. They do indeed.

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  • Doesnt seem like a good idea to me. Sorry. Especially for cleaning. If its your spirit still then cleaning wont be much of an issue bit if you use it for stripping you need to clean it and scrub it.

  • I'd be more inclined to put some copper fittings/couplers or ceramic rings in the boiler, anything to act like boiling chips rather than scuffing up the boiler.

  • "I do the stupid stuff so you don't have too" should be my catch phrase.

    So round one did nothing. Zero effect. I'll move on to some heavier grit and see what happens. I looked at the other options but I prefer the once where I don't have to add or remove extra things.

    This would help spirit runs. I've not had an issue with stripping runs as the particulate in the mash creates it's own nucleation sites.

  • edited May 27


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