distillation separates spirit from phlegm

An example of a term used by analogy,

"In the early 19th century, many formerly artisinal processes were scaled up and intensified as part of the Industrial Revolution. Distillation was well-established as a technique, and production of various kinds of hooch was growing steadily. This involved heating a fermented mash at the bottom of a pot still to separate the more volatile 'spirit' from the heavier aqueous 'phlegm'."

Sella, Andrea (2023), Sorel's plates, Chemistry World, 20 (5), https://www.chemistryworld.com/opinion/sorels-plates/4017311.article

In alchemy the phlegm was the residue after a separation process such as distillation. In ancient Greek medicine, phlegm was one of the four bodily humours (that needed to be in balance for good health). A key feature of traditional thinking (for example, influencing alchemy) was the notion of correspondences in nature – that the body reflected the wider cosmos, as there were correspondences between earth and the heavens.

The term 'spirits' for distilled alcoholic drinks is still in use today.