Dregs, lees
Archimandrite Nikifor’s Biblical Encyclopedia
(Ps. 75:8 [74:9]; Jer. 48:11) — the sediment left from wine. New wine was often poured onto the lees of old wine, probably in order to strengthen its body, aroma, and preserve its color. It is to this, no doubt, that the prophet Isaiah alludes when he compares spiritual blessings and the triumph of gospel preaching to the very purest wine — wine on the lees. Before wine was used it was clarified of its lees, and such wine was called “refined.” To drink the dregs signified a certain degree of punishment (Ps. 75:8 [74:9]).
The prophet Jeremiah (48:11) says of the Moabites, and the prophet Zephaniah (1:12) of the Jews, that both “settle on their lees” — an expression probably indicating that they had become good for nothing, incapable of moral purification.