What is the 'tails' in distillation?

In distillation, 'tails' refers to the last portion of the distilled liquid that is collected, which includes high-boiling compounds. As distillation progresses, components of the liquid are separated based on their boiling points. The 'heads,' or the first distillate, typically contain lighter, more volatile compounds, including some of the more desirable flavors and aromas. As the process continues, the 'hearts' come next, which are more palatable and contain the majority of the ethanol desired in drinks.

When the distillation reaches the 'tails,' the temperature continues to rise, leading to the extraction of heavier compounds that are often not suitable for consumption, such as fusel oils and other higher-boiling substances. These can impart undesirable flavors and aromas to the spirit. While tails can sometimes be collected and re-distilled for certain applications, they are generally used sparingly in making spirits to maintain quality and flavor.

This illustrates how the distillation process is carefully controlled to harvest only those components that will contribute positively to the final product, making the identification of 'tails' crucial for distillers aiming to create high-quality spirits.