Potstill Purity Calculator

Pot Still Calculator

This tool estimates heat-up time, stepwise collection volume, and purity for a pot still run.

Calculation of a Pot Still Distillation Run

Here’s a rough stab I’ve had at this....

One assumption is that all the heat input is used to vaporise the vapour, eg no heat losses, but this should be a minor error. (I’ll just claim that all pot stills are extremely well insulated ...)

If you don’t know what your power input is (say you are using gas heating instead), adjust the value used until the “time to heat up” is close to what you expect.

This can also be used for double & triple distillations, eg:

• 20 L of 15% will give around 6 L of 45% (use say a 25% cut-off)
• feed this back in & see that you’ll get around 4 L of 68%
• distilling this gives about 3.4 L of 80%

It’s not quite such an accurate calculation at the higher % alcohols, because the timesteps are too large. An indication that the calculation has got where it’s going is when the sample purity first goes negative.

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Input your Pot still characteristics

           Initial Volume of Wash
            L

           Alcohol Content
            % by volume

           Initial Temperature
            C

           Power during Heat-up
            W

           Power during Distillation
            W

           % Internal Reflux
            %

           Time-step for calculation
            min

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Change any of these values & see the difference in the table below ...

Calculate Results

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Results

           Time to Heat up Still contents
           

Time	Temp	Collected	Purity	Total Collected	Total Purity