“You should always hold the glass by the stem, no matter what the shape or size of the glass or the type of wine,” says Michael Greenlee, the sommelier and wine director of Gotham Bar and Grill, in New York City. “The most common mistake I see in restaurants and at dinner parties is people holding a wineglass by the bowl.” When you do this with a Champagne flute or a wineglass, your body heat warms the drink inside. Of course, white wine and Champagne both taste best when they’re chilled. Holding your glass of Burgundy by the bowl will not affect its taste, but “if you’re trying to look at the color and the clarity of the wine, it’s hard to see them when your hand is wrapped around the glass and you have fingerprints on the bowl,” says Greenlee. So pinch the stem between your index finger and your thumb. If holding the glass by the stem feels unwieldy, check the portion: A wineglass should be only a quarter to a third full.