At New York City’s Union Square Café, flat Champagne becomes a vermouth, showcased best in the restaurant’s House Martini.

“We have a very strong private-dining business,” says Beverage Manager Ryan Chavis. “Every now and then, we would have leftover Champagne from a party.”

In keeping with the restaurant’s mission to reduce waste, he allows the bottles to “rest” overnight until the carbonation subsides. He then infuses the wine and adds a neutral spirit so that it lasts several weeks (recipe below).

The end result is a blanc vermouth with apple and honey notes, which Chavis mixes with Neversink, a New York gin distilled from apples.

Hot, Cold or Re-fermented

At Los Angeles’s Bar Clacson, co-proprietor Eric Alperin brews a nuanced “Champagne syrup” to sweeten an Aperol Spritz variation that dissolves equal parts sugar and flat bubbly over gentle heat.

You can also freeze once-sparkling wine into ice cubes for sangria or highball-style cocktails. Be advised, however, they melt relatively quickly since there’s still some lingering alcohol.

Another option is to allow the flat wine to ferment into a rustic Champagne vinegar. Chavis has tried this to much success, too, and likes to macerate the vinegar with fresh fruit to make shrubs.