Prep the grapes: Remove grapes from stems, wash, and thoroughly pat dry with paper towels. Removing moisture helps the sugar stick.

Macerate briefly: Place grapes in a bowl and drizzle with Champagne (about 1/4 cup). Toss gently to coat and let sit 5–10 minutes to take on a hint of sparkle and flavor. For a nonalcoholic version, use 1/4 cup chilled sparkling water or club soda with a teaspoon of lemon juice.

Sugar the grapes: Pour the granulated sugar into a shallow bowl or plate. Working in small batches, roll each damp grape in the sugar until it is well-coated. Shake off excess. For a glossier look, use superfine sugar.

Chill to set: Arrange the sugared grapes in a single layer on a parchment-lined baking sheet and place in the freezer or refrigerator. Freeze for 30–60 minutes or refrigerate for 1–2 hours. The cold crisps the sugar and makes the grapes extra refreshing.

Serve: Transfer to a chilled bowl or use as a garnish for coupe glasses, champagne flutes, or desserts. Serve immediately for the best crunch.