Inside the House is a DCist feature offering an insider’s view of fine dining issues by the hostess at a D.C. restaurant.

By DCist contributor Nadya S. Nikiforova

No restaurant custom may appear as vague to the infrequent or uninitiated diner as “bring your own bottle” — also known as the corkage policy. The fact is, most restaurants will allow guests to bring a bottle of wine to enjoy with their dinner for a fee of anywhere between $15 and $30. Considering that most diners believe restaurant wine prices are outrageously inflated compared to retail, this service may seem like a nifty way to shave a few bucks off your dinner bill.

A word of advice on using corkage to save money: don’t do it. And why not? Because the corkage practice was never meant to be loophole for those who want to avoid paying the restaurant markup. This service was conceived and adopted by restaurateurs as a courtesy to guests who wanted to enjoy a special, rare, or sentimental value wine with their dinner. Such as a special vintage bottle lovingly carried over from your last voyage to Napa Valley or France. Or the wine from the same vineyard that catered to your wedding party that you want to enjoy over your 20th anniversary dinner. Or something otherwise remarkable that the restaurant does not carry on its wine list — not a $12.99 bottle picked up at the corner grocery store on the way to dinner.

The restaurants — being in the food and wine business and all — can usually tell the difference between good juice and cheap swill. It might be easy to think that corkage fees are pure profit for the house, but ensuring proper wine service at the table takes work that doesn’t necessarily get reflected in your bill. It takes decanters, ice buckets, hand-polished wine glasses, and staff time taken away from other tables.

With that in mind, how should a savvy diner go about bringing a bottle?