According to Willie Gluckstern, compiler of countless New York City restaurant wine lists and author of The Wine Avenger (Simon & Schuster, $12, www.amazon.com), sniffing the cork is "akin to wearing a big 'Schmuck' sign on your forehead." Truth is, little information about a wine can be gathered from the cork. "The only thing that's revealed is your naivete," says Gluckstern.

There is a way, however, to determine if a bottle of wine is "corked" and therefore undrinkable: The wine may smell moldy and have an astringent taste. You are entitled to refuse an unsatisfactory bottle in a restaurant and to be reimbursed for one by a wine store.