It can take just 90 seconds and a rubber band. Curious cooks have begun hacking carbonators, the soda-making machines that are proliferating in American home kitchens. Most buyers are happy to use them for their intended purpose: turning tap water into sparkling water. But off-label, they have been used to make herb-infused sparkling wine, newfangled sangria, heady cocktails and nonalcoholic — but intoxicatingly delicious — sodas. Recently, in a storefront laboratory in Chinatown, Piper Kristensen, a bartender and occasional lab assistant who works for the avant-garde bar Booker and Dax in the East Village, studied a SodaStream Penguin. It had...