Disposable coaster

A disposable coaster for use with a beverage container comprising a substrate of moisture absorbent material, said substrate having a base panel and a pleated sidewall joined to the base panel thereby forming a shell having an open end, with the moisture absorbent substrate forming the inside surface of the shell, and a sealing film deposit applied to the outside surface of the shell, said pleated sidewall including folded, vertically overlapping major and minor fold segments which define a vertically extending reservoir for accumulating moisture, the major and minor fold segments being partitioned by an inwardly disposed upright crease and an outwardly projecting inclined crease, respectively, said outwardly projected inclined crease sloping upwardly and outwardly from said base panel whereby said outwardly projecting crease is inclined with respect to and extends transverse to said inwardly disposed upright crease, thereby defining a reservoir space into which condensate can flow by capillary action.