To make 6 sparkling Negronis, start with good sweet vermouth
You'll be filling your carbonating bottle with enough booze for 6 servings, but you'll stir it all over ice first to add just the right amount of water and to properly chill the liquid before carbonating. Set up 3 large mixing glasses, and add 2 ounces of Carpano Antica sweet vermouth to each glass. Make sure your vermouth is fresh!
Then the Campari
Add 2 ounces Campari to each glass as well.
Then the gin
Add two ounces of gin (such as Plymouth) to each mixing glass.
Pour into Isi carbonating bottle
Pour stirred cocktails into Isi carbonating bottle. If you don't have a mixing glass with a pour spout, you may want to use a funnel to avoid splashing. At this point, you can seal the bottle and keep your bottled Negronis in the fridge until ready to serve, or carbonate immediately as long as the bottle is cold.
The downside of the Isi is that the charging capsules are one-time use. Buying in bulk can lower the cost of the chargers to around 50 cents each, though. Insert charger into Isi 'sparkling wand'.
Twist on the Isi's 'sparkling wand' according to package instructions and let it get fizzy. Lieberman sometimes carbonates his Negronis twice for extra bubbles.
Though a Negroni is typically served with an orange twist, Lieberman likes a grapefruit twist with the carbonated version. Squeeze grapefruit peel over the surface of the drink to express the oil, then add the twist to the cocktail as a garnish.
Caught in the act