Wash the grapes thoroughly under running water. Seedless grapes are easier to eat, but seeded ones work too.

Detach each grape from the stem and place them on a paper towel.

Optional: Trim any unsightly parts of the grapes with a knife.

Dry the grapes thoroughly using a paper towel or let them air dry.

Prepare a ziplock bag and line it with a layer of paper towel.

Fill the ziplock bag with the grapes, seal it tightly, and press out any excess air.

Place the bag in the freezer and let the grapes freeze overnight.