Removing the Foreshots
Be sure to toss at least the first 50 mL (off a 20L wash) that you collect, which are
, as this contains high esters and other off-flavors.
These can be used as a solvent or ant killer or any number of useful purposes.
Jack writes ..I have tasted potstill alcohol that has
been made both ways- when only 50ml (per 20L) was thrown out, the stuff was
very sharp tasting. It became alot smoother when a full 100ml was thrown
out at the start of the run.
This first portion is often called the "foreshots".
They are different from the "heads". Ian Smiley (http://www.home-distilling.com/)
describes foreshots as "the low boiling point compounds that
come out of the still first. They contain acetone, methanol, various esters and aldehydes,
and other volitiles. Foreshots are to be considered poisonous and should be discarded."
Whereas heads "come out after the foreshots, and are almost pure alcohol, except that
they are contaminated with trace amounts of unwanted cogeners ..." To get a really clean
distinction between the foreshots and the heads, first ensure that you've let your
column equilbriate under total reflux, then hold the reflux ratio high, such that you remove
the foreshots only very slowly (eg 1 drip per second), thus allowing an equilbirium to
be maintained at the top of the column, encouraging the methanol to collect there.
If you're after making pure neutral spirit for vodkas or gin you may choose to
keep the heads (eg the next 250 mL-1L of spirits) separate from the following couple
of litres (middle run) on the basis of their taste. These heads can still
be used to make liqueurs, whisky, rums, etc, or redistilled later if desired
totally neutral. The only problem with heads is their non-neutral taste.
The distinction between the various phases depends on what sort of still you have.
They will all tend to merge from one to the other. This is particularly the case with
a pot still, where you notice the temperatures always slowly changing as the distilling run progresses. Using a reflux still or fractionating column will allow the various stages to appear more distinct, as the temperature will be more stable, due to the more distinct seperation of each compound.