Take-Off Rate Calculator

This is the reverse of the Run Time Calculator. Instead of estimating how long a run will take at a given rate, this solves for the rate you need if your available time is fixed, useful when you know you only have a few hours today and need to know if that's realistic.

The result is checked against the range most home pot stills can maintain good separation at, roughly 50 to 150 mL per minute. If your required rate falls outside that range, the calculator flags it so you can adjust your plan rather than find out partway through the run.

Take-off rate and separation quality trade off directly. A slower rate gives the vapor more time inside the still and any column or reflux path to re-equilibrate, which sharpens the transition between heads, hearts, and tails. A faster rate moves more volume per hour but blurs those transitions, since the vapor composition doesn't have time to fully settle before it's collected.

Reflux and column stills tolerate faster take-off better than a simple pot still, since the packing or plates provide additional separation stages that a plain pot lacks. If you're running a pot still without reflux, staying toward the lower end of the safe range matters more for cut quality than it does on a well-packed column.

If the calculator flags your required rate as too fast, three realistic options exist rather than forcing an aggressive take-off:

Reduce the batch volume. Running a smaller charge in the same time window brings the required rate back into range without changing your schedule.

Split into two sessions. Running half the volume today and the rest another day keeps every run at a comfortable pace.

Accept a wider hearts cut. If neither option works, running faster with a more conservative (narrower) hearts cut reduces the risk of heads or tails character carrying through, at the cost of a smaller finished yield from the same wash.