beeswing

Noun

 * 1) A filmy, translucent crust found in port and other old wines which have been bottled-aged for a long time.
 * 2) Cream of tartar; potassium bitartrate; the residual salt of tartaric acid.
 * 1) Cream of tartar; potassium bitartrate; the residual salt of tartaric acid.