vacuum potstill

Simple pot still distillation and construction with or without a thumper.

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distillerboy
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vacuum potstill

Post by distillerboy »

hello, i'm planning to build a vacuum potstill, anybody have diagram or info on it ? pls help
rednose
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Re: vacuum potstill

Post by rednose »

The are some topics that handle this theme on reflux stills but none is complete.

Hopefully some vacuum users chime in to get the needed information.

I'm also interested in this topic and was collecting as much info as possible all over the net but there are so many open questions.

Joe
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Pikluk
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Re: vacuum potstill

Post by Pikluk »

im very curious about the quality of a vacuum distillation
specialy if you go on a perfect vacuum iv seen cold water boil
like i had my hand on the boiling vessel and is was cold "drinking water cold" and boiling.
and i saw what regular store bought beer look like after been boiled at 174 it get all the floating stuff that look like pieces of grease / fat.
boiling a wash and or mash have to alter taste of distillate (at 174 +)
in a good way i don't know
maybe distilling under vacuum would give the best stuff ever.

just a wild question here
any distiller selling/promoting there product because its been made on a mountain high in the sky? very high altitude can change boiling point from a bunch of degrees

most vacuum distillation is made in labs to prevent the main product to be altered by heat, some product have a evaporation point so high that they get destroy before they reach boiling point so under vacuum they can be distilled without destroying them.
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loneswinger
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Re: vacuum potstill

Post by loneswinger »

There are some folks around that do it. If I remember correctly, most are in Iceland where hot water is cheap and they can use it to heat the boiler. Energy wise there is no real advantage. In fact it takes more energy at lower pressures and temperatures to boil substances. http://en.wikipedia.org/wiki/Enthalpy_of_vaporization So unless you have a cheap source of heat that is to cold to distill at ambient pressure, then it isn't worth it.

(Unless you are distilling something else besides alcohol that is heat sensitive of course).

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MuleKicker
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Re: vacuum potstill

Post by MuleKicker »

I know for a full vacuum, you would need one hell of a cold condenser. That is gonna take some energy.
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rednose
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Re: vacuum potstill

Post by rednose »

I really would love to learn from a vacuum still operator.

A friend of mine is experimenting to extract natural color from a seed, he want to soke the seeds in high ABV and later get the alcohol out, he will have a color mud to process.

The problem is that he can't go higher than 70 C without distroying the color, therefor the only chance would be vacuum distilling at maybe 50C as we have well water of about 25C for cooling.
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Re: vacuum potstill

Post by loneswinger »

Yes rednose,

This would be the one advantage is if you had something fragile to distill. I have had some experience with vacuum distilling in an organic chemistry setting using glass distillation equipment. It was actually straight forward, heating was done with a warmed oil bath, cooling was done with a recirculated ice/salt water solution and the vacuum was pulled with a water aspirator. The vacuum is pulled from the collection vessel end of the setup. This was very small scale though.

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Re: vacuum potstill

Post by MuleKicker »

Yes, at extreme vacuum you would need a AC system with the evaporator as your product condenser to even get close to the cooling capacity you will need.
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Re: vacuum potstill

Post by loneswinger »

MuleKicker wrote:Yes, at extreme vacuum you would need a AC system with the evaporator as your product condenser to even get close to the cooling capacity you will need.
Well it depends on the vacuum, but yeah, you just can't beat energy conservation.

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Re: vacuum potstill

Post by MuleKicker »

loneswinger wrote:
MuleKicker wrote:Yes, at extreme vacuum you would need a AC system with the evaporator as your product condenser to even get close to the cooling capacity you will need.
Well it depends on the vacuum, but yeah, you just can't beat energy conservation.

-Loneswinger
true. If you want to go with some serious vacuum, its gonna take some serious cooling. I would think that the energy you save in heating, you would use in cooling. (I know something was said about more energy needed to boil under vacuum) I dont understand that. As you can boil water at room temp with enough vacuum, and no heat input. I have an AC vacuum pump that will boil water at room temp, i have thought of using it to make likker. Just havent done the reseach to put it to use yet. All in good time. :D
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Re: vacuum potstill

Post by loneswinger »

I am the one that said it takes more energy at higher vacuum (lower temperature). Temperature and energy are not the same thing. Yes, you can boil at room temp, but you will need something feeding it that room temp or it will quickly cool and stop boiling.

Have you ever ran your propane tank for so long that the liquid is cold and you get very little to no output? You have to supply that cold liquid with energy to get it to boil, and it is at -40, well below room temp, and it still won't really boil on its own. Do you see what I am saying? The pressure changes the boiling temp, but that doesn't change the fact that you have to feed it energy to get it to boil. All I am saying is that you can not just pull vacuum and expect it to keep boiling, it won't, you will have to at a minimum circulate room temp water around it or something to keep heating it.

Also on the cooling end. If you had a vacuum strong enough to boil your wash at room temp (around 10 mm Hg), like you said, you would need something very cold to condense the vapor and the energy would get you there.

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