CUT
The foreshot is the first fraction that runs off during distillation. The foreshot is composed firstly of methanol, which is toxic to humans (even in small quantities it can cause blindness and death), and secondly of aldehydes and acetone, a substance used in industry as a solvent, and other volatile compounds. Naturally the foreshot has to be separated off and discarded.
An experienced distiller knows exactly when the foreshot can be separated and the spirit (heart of the run, or middle cut) used. In terms of quantity the foreshot is insignificant.
The feints (which run off after the middle cut) are of low quality, but not harmful to health. They contain fusel alcohols (headache!), fatty acids and other undesirable substances. For the experienced distiller, the point at which to separate the spirit from the feints is not difficult either.