You now have a syrup that you can carbonate with seltzer water; I use my iSi soda siphon for some nicely-textured bubbles. To assemble a gin and tonic, use ¾ ounce of syrup, 1½ ounces of gin and 2 ounces of soda water over ice. Recipe printed courtesy of jeffreymorgenthaler.com...
While the soda siphon is easier to use, for the sake of authenticity you might want your ginger beer fermented in the bottle. If you’re going to go the iSi route, pick up a soda siphon and meet me at the next step. The rest of you, follow me. The first thing on your list if ...