The word shrub, like sorbet, sherbet, and syrup, all are derived from the Arabic word sharab meaning beverage. Pre-refrigeration, the only way to preserve fruit juices were to douse them heavily with sugar, alcohol, or vinegar. In the regions of Turkey and Persia, where there was a dense population of people of the Muslim faith, the drinking of alcohol was prohibited, and vinegar was the preservative of choice.
Trading ships in the seventeenth century brought these fruity acidic beverages back to Western Europe where the drink flourished. Eventually, it made its way to colonial America, where it became wildly popular, though by the time it made it here, it should be noted, it was often blended with rum or brandy.
There is the story that shrub was used to mask the taste of seawater-tainted rum. It might just be simply an amusing tale, but there could be some truth to it. Thanks to the vitamin C in the vinegar, it is an antiscorbutic, which means it could help prevent scurvy. Sounds like a double win for the sailors of the time to me.
I find the science behind these beverages fascinating, check out this breakdown from Ph.D. biochemist, Frederic Yarm, whose love of drink history and science led him to become a cocktail writer and professional bartender.
“When a shrub ages, it’s like an ecosystem. Ambient yeast (that is, the yeast on the fruit itself and yeast from the air) turns the sugar into alcohol, and the Acetobacter (the bacteria in unpasteurized vinegar) turns the alcohol into more vinegar. In this symbiotic relationship, the Acetobacter feeds on the yeast’s metabolic waste products, and this removal then stimulates the yeast to continue to make alcohol. Eventually, this will stabilize and not turn the whole shrub into fruit vinegar, since the bacteria-induced pH change will stall out the yeast’s fermentation process. The end result will be a different flavor profile than just the initial fruit, vinegar, and sugar blended mixture; this change would be comparable to how fresh-pressed grape juice morphs as it becomes wine due to the microbial byproducts such as polyphenols created during the ferment.”
The result of this process is tangy and enchanting. Super refreshing. In the heat of the day, I like to mix my shrub with a little sparkling water and drink it ice cold. Next time you catch it offered on a menu, I highly recommend giving it a try.