THE FERMENTED goodness of vinegar has informed refreshing "shrub" cocktails for hundreds of years. The tradition started in England as early as the 17th century, when vinegar was used as a substitute for expensive citrus to preserve seasonal fruit.

Once the fruit was removed, the liquid was cooked down to a tangy, fruity elixir mixed with other liquids or liquors.

"Shrub was the most popular mixed drink in the Colonies," said Walter Staib, chef/proprietor at City Tavern, the Society Hill eatery devoted to recreating authentic Colonial cuisine. The raspberry shrub on Staib's bar menu is based on a recipe from Martha Washington and served on the rocks or with champagne for a zippy twist on the mimosa.

Flavor-crazed bartenders are finding shrubs to be the perfect addition to a vivacious craft cocktail menu.

"My mom always made shrubs in the summertime for our family," said Ross Maloof, bar manager at Center City's Vedge, the gourmet vegan restaurant from Rich Landau and Kate Jacoby. "There is nothing more refreshing than a shrub mixed with club soda, as the vinegar brings down the sweetness of what would otherwise just be lemonade."

Although you wouldn't know it from the drink names, and there is no taste of vinegar to be discerned, vinegar-based shrubs add complexity to cocktails at both Vedge and V Street, Landau and Jacoby's new global vegan street-food eatery on 19th Street. At Vedge, Maloof creates a Thai-basil beet shrub for a drink called the Moneygoround, and a pineapple-rosemary-Meyer-lemon shrub for white sangria.

At V Street, beverage manager Daniel Miller described vinegar as "essential to the cocktail program."

The best-seller on Miller's creative menu is Colonel Mustard in the Library With a Dagger, a twist on a classic Corpse Reviver No. 2, with sherry vinegar instead of citrus, and a subtle mustard syrup that makes this drink impossible to categorize and completely irresistible.

"Vinegar just adds depth to a drink," said Miller. "The kitchen relies on it in many of the dishes we serve, so it makes sense that vinegar can add harmony and balance to our cocktails."

- Beth D'Addono