Is the sommelier’s pretasting your bottle an expert service or an excuse for a sip of your very expensive wine? Here, the pros and cons.

SHOULD THE SOMMELIER taste your wine before you do? It seems like such a simple question, and yet it is one that can provoke a surprisingly heated debate among oenophiles—professionals and amateurs alike.

Wine drinkers who answer in the affirmative might point to a long history of wine service that dictates the sommelier sample each bottle before it is served. Common in more formal (and mostly French) restaurants—or establishments where there is a particularly complex or expensive list—the practice is meant to ensure diners don’t unwittingly end up with a wine that was corked, oxidized or otherwise flawed. (Corked means infected with a chemical compound called trichloroanisole, or TCA; oxidized refers to a wine that has been somehow exposed to oxygen, which has a deleterious effect on wine over time.)