In a food processor, puree champagne grapes. Let mixture sit for at least 20 minutes.
Strain the puree through a fine mesh basket strainer into a metal bowl, pressing skins to squeeze out as much juice as possible. Whisk in wine, lemon juice and sugar (taste and add more sugar if needed).
Cover with plastic wrap and freeze mixture for 2 hours. Take the bowl out of the freezer and scrape the icy bits from the edges to the center.
Repeat this scraping process every 30 minutes until the entire mixture is frozen and flaky.
Notes
*Can’t find champagne grapes? You could also use green, red or black seedless grapes. If you want to use red or black grapes, I would recommend using 1 cup of red wine rather than the white wine.