Getting rhubarb into a cocktail is no easy matter.
Unlike citrus, it can’t be easily juiced behind a bar, or muddled at the bottom of a low ball glass.
But it does work beautifully in a shrub.
Shrubs, as described in Jerry Thomas’s 1887 “Bon Vivant’s Companion,” combine fresh fruit, an acidic element (juice or vinegar) and sugar. They may contain alcohol, usually rum, brandy or whiskey, though that’s not a requirement.
At L’Etoile, bartender Ruben Mendez recently made a non-alcoholic rhubarb-honey shrub that tastes like a sophisticated lemonade. For the Breath of Fresh Air cocktail, he combines equal parts shrub and cucumber-infused gin with Lillet Blanc and a lemon twist.
“It gives you another way to put acid into a drink,” Mendez said, as he chopped stalks of rhubarb for another, alcoholic batch.
Mendez steeped the new bunch of rhubarb in red wine vinegar he makes at home. He then spiked the mix with Cane and Abe Freshwater Rum (made by Old Sugar Distillery on the near east side) and left it to sit overnight.
“You could almost call limoncello a shrub, because it’s alcohol and peel and you add sugar at the end,” Mendez said. By the definitions in Thomas’s cocktail guide, cherry bounce (cherries, sugar and brandy) would also be a shrub.
Behind the bar, herbs and fresh fruit tend to go bad quickly, Mendez said. Shrubs can preserve their flavor almost indefinitely.
“Shrubs I’ve come up with in the past have been at that rescue stage,” Mendez said. “I have tangerine gin, tangerine tequila and tangerine juice. What am I going to do with it all, because I had very little of each? I threw it all together and it became a shrub.”
Shrubs have grown in popularity alongside the increased interest in craft cocktails. Merchant has a few behind the bar — watermelon-kiwi, blueberry, blackberry — though none are currently used in cocktails.
Cookbook author Aida Mollenkamp wrote late last summer about favorite combinations, like tomato-balsamic-pepper, plum-sherry-star anise and peach-cider vinegar-rosemary.
For a simple berry shrub, Mollenkamp’s recipe (below) requires almost two weeks of steeping and includes no alcohol.
Mendez’s shrub, loosely adapted from Thomas’s book, is faster. It involves simmering the fruit-infused rum and vinegar for about 10 minutes, adding sugar, letting it cool and adding more rum.
After the shrub is done, Mendez plans to keep the leftover rhubarb and cook it down with wine and sugar. Then he’ll puree it into a sauce, a culinary technique called a gastrique.
“For spring and summer fruits, I want to go for the unconventional,” Mendez said. “I’m tempted to use herbs with it,” like a pineapple sage that smells intensely of tropical fruit.
Part of the benefit for bartenders who make their own is speed. Mix a shrub with soda water or sparkling wine, and you have an instant, delicious cocktail.
Lindsay Christians occasionally pours tastings at Barriques.