Cuts Calculator

Separate. Foreshots, Heads, Hearts and Tails are four disjoint slices of Total Distillate Collected and add up to it exactly, so Foreshots is the first jar you fill and Heads is what comes after it -- do not subtract one from the other. Foreshots is the one cut that is always discarded outright rather than saved for a later feints run, because it concentrates methanol and acetaldehyde.

The published rules of thumb are volumetric and scale with wash volume, not wash strength: an absolute minimum of 150 mL of foreshots per 25 litres of wash on a pot still, with a common working range of 5 to 10 mL per litre of wash, and around 50 mL per 20 litres on a reflux still. This calculator reports whichever is larger -- that volumetric rule, or 5% of your collected run -- so the Foreshots figure is a floor to discard at least, not a target to stop at. Discarding more early run costs you a little yield; discarding too little is the mistake that matters.

Yes for Wash Volume, and almost exactly for Wash ABV. Heads, Hearts and Tails are fixed percentages of Total Distillate Collected, and Total Distillate Collected is Total Alcohol in Wash (Wash Volume times Wash ABV) divided by the Assumed Collection ABV, so doubling either input doubles all three. Foreshots is the exception: it is floored at a per-litre-of-wash safety rule, so doubling Wash Volume doubles it, but doubling Wash ABV on a weak wash may not move it at all -- the floor is still governing.

Treat them as a planning estimate rather than a precise cut schedule. Real distillers set foreshots, heads, and tails cut points by smell, taste, and often hydrometer or spirit-safe readings as the distillate actually comes off the still, because the real proportion of congeners depends on your specific wash, yeast strain, and fermentation, which this fixed-percentage model can't see. Use the estimated volumes to plan collection vessels and timing, then adjust by your senses during the actual run -- and when in doubt, err toward discarding more of the early run.