How is the heads fraction defined in distillation?

The heads fraction in distillation is defined as the first portion of the distillate, often referred to as foreshots. This phase contains volatile compounds that evaporate at lower temperatures than the desired alcohol, including methanol, acetone, and other light esters. These compounds can impart undesirable flavors or effects if consumed. During the distillation process, the distiller separates these heads from the hearts (the main portion intended for consumption) and the tails (the final run-off that contains heavier compounds). By ensuring the heads are removed, distillers can improve the quality of the final product, focusing on the more palatable and aromatic components found in the hearts fraction.