Technique: ISI whip with CO2, 1 hour before service — fill the canister with green grapes, charge with one CO2 cartridge, let stand 1 hour. Discharge slowly to release. Grapes will be effervescent on first bite.
Alternative: Fresh green grapes day-of (no carbonation), used as visual garnish.
Used in:
Prep: 1 cluster per service worth, batched morning of.
Visual cue: Taut skin, slight effervescence (you can feel the fizz on your tongue if you bite one).