Calculation of a Pot Still Distillation Run
Heres 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
- 20L of 15% will give around 6L of 45% (use say a 25% cut-off)
- feed this back in & see that you'll get around 4L of 68%, then
- distilling this gives about 3.4L of 80%
It's not quite such an accurate calculation at the higher %alcohols, because
the timesteps are too large. An indication that that calculation has got
where it's going is when the sample purity first goes -ve.