moldy
A moldy smell or flavor is generally a signal that a wine was either made from moldy grapes or stored in deteriorating or improperly cleaned barrels. See also corked.
The New Wine Lovers Companion, 2nd Edition, by Ron Herbst and Sharon Tyler Herbst. Copyright © (1) 2003, 1995 by Ron Herbst and Sharon Tyler Herbst. Reprinted by arrangement with Barron's Educational Series, Inc.