Why Does My Espresso Come with a Twist of Lemon?

Lucky patrons who order a petite-sized cup of bittersweet espresso might joyfully discover it is served alongside a gratis sphere of buttery shortbread or disc of dark chocolate, perhaps. Others will be confounded upon spotting a thin swath of lemon peel on the saucer. What, exactly, is one meant to do with this colorful component?

Folklore dictates that the lemon should be rubbed on the cup’s lip before first sip. But why, you ask? It’s a good question, it turns out — and one that confounded the many experts consulted. Some say this curious ritual was meant to quell illness, while others believe the aromatic oil the peel elicits was intended to mask shoddily made coffee. One myth claims that during water-scarce World War II, lemon provided an alternative to much-needed sanitization; yet another tale purports an Italian-American restaurateur merely wanted to unite his passions for java and citrus and the duo was born.

Or perhaps it’s just a marketing gimmick: Because Italy is abundant in fragrant lemon trees and the Amalfi Coast in particular is home to the lemon zest liqueur limoncello, it’s rather easy for a café to sell a glamorously named, overpriced caffeinated concoction that conjures a seductive country via the presence of an elegant peel.

Coffee purists will tell you, however, that if the barista is doing his or her job, you wouldn’t dare add lemon peel to a shot of espresso. When espresso is pulled correctly, “all the constituent parts harmonize and there is no need for any additional acid, explains Brett Robison, beverage manager at Republic in Takoma Park, Maryland, and former head bartender at Washington, D.C.’s Tryst Coffeehouse Bar & Lounge.

To get a bit geeky, Robison says you should think of coffee as “ninety-five percent water with dark, solid bean matter, naturally occurring tannins, acid, and oil” – and you want all these constituents to be in balance. “With overly hard water or long and heavy extractions, you will have too many tannin compounds that lead to an overly smoky, bitter coffee,” notes Robison. At the other end of the spectrum, too early an extraction will yield an espresso that is too high in acidity. And you’ll get the same result by adding the oil from lemon peel, which includes the acidic, citric solvent also known as citric acid.

Ultimately, adds Robison, it’s a matter of taste. “Flavor is a combination of aroma, texture, sensation, and visual cues. What may be the ideal espresso for one might require citric acid.” A jolt of lemon might just be crave-able in someone’s morning joe.

What do you think? Do you like your espresso with a smack of uplifting citrus?