By its classical definition, a punch is made up of five components: water, citrus, alcohol, spice and oleo-saccharum. The last ingredient might sound like the scientific name for a pelvic bone, but it’s actually a mix of citrus oil and sugar. And it’s a non-negotiable component of good punch, top bartenders say. “If there’s no oleo-saccharum, it’s not a punch,” says Dillon Lockwood, bartender at San Francisco’s punch-centric Novela. “It’s like calling something a martini just because it’s served in a martini glass."
To make oleo-saccharum, simply peel oranges or lemons (never limes, their skin is too bitter), muddle the peels with sugar and let the mix sit until the oil emerges from the skins—about half an hour. Strain, and you have the base for the best punch ever.
According to Lockwood, oleo-saccharum lends a subtle but vital backbone of flavor. “It creates an even base of refreshing citrus,” he says. “It’s not intense, but it’s noticeable.”