What are lees?

If you read the ingredients listed in the wonderful 40 Knots soaps, you may wonder (as I did) exactly what lees are!

Lees refers to deposits of dead yeast or residual yeast and other particles that precipitate, or are carried by the action of "fining", to the bottom of a vat of wine after fermentation and aging. The yeast deposits in beer brewing are known as trub.