It started as a quest to perfect the Mai Tai.

I was tending bar at The Slanted Door, a Vietnamese restaurant in San Francisco, where my bar manager and I loved to argue about cocktail minutia. Like many bars in 2007, our version of the Mai Tai was a rum and juice mixture—pink of course—lacking the characteristic marzipan flavor lent by orgeat, an almond syrup essential to the original recipe. Traditionally, orgeat was made from whole almonds, but since the industrialization of food, this labor-intensive product was usurped by extract-flavored versions. After a bit of research and a load of testing, I began making a 19^th century-inspired version with California-sourced ingredients. Eventually, my company Small Hand Foods was born, and five years later I’m cooking up batches of orgeat, grenadine, gum (plain, pineapple and raspberry versions) and tonic syrups to ship to bartenders and clients across the country. Perfecting pre-Prohibition era products has benefited my approach to bartending, allowing me to blend the wisdom of history and the efficiency of modern techniques.

For me, even the most basic of ingredients has the potential to become a well-researched science project.

This is a lot of history for one fact most pertinent to cocktail folk (and agro-history nerds):  if you want to recreate a recipe published before 1926 that contains lime juice, the author based that recipe on Key limes.

Take the lime. It’s an essential building block to the daiquiris Hemingway drank, and the tonic 19th-century sailors consumed to thwart scurvy. However, not all limes are created equal. The limes we find in grocery stores today are Persian limes, a.k.a. the Bearss lime, a variety developed by John T. Bearss in California in 1895. They were bred to be seedless, larger and thicker-skinned than Key limes—the more widely used variety at that time—so they would be hardier for transport and provide more juice per fruit. This Persian lime is a modern crossbreed named for the region where the lime was first grown. Ironically, what we know to be Key limes were originally grown in Persia, but Spanish exploration in the 15^th century prompted a global biological mash-up, and plants, animals and people were suddenly inserted into new regions around the world. When Columbus introduced the lime to the Americas, the fruit was christened according to its new, tropical locale. Until two hurricanes decimated Florida’s groves in 1926 and 1928, the Key breed ruled as America’s common lime. Subsequently, Bearss’s new variety swept the country.

This is a lot of history for one fact most pertinent to cocktail folk (and agro-history nerds):  if you want to recreate a recipe published before 1928 that contains lime juice, the author based that recipe on Key limes.

Charles H. Baker Jr.—a late 19th- and early-20th century world traveler, bon vivant and writer—chronicled both lime varieties in his hilariously florid prose during a string of South American wanderings. While he doesn’t mention them by name, he does call for “small” or “large” limes, and sometimes “green” limes as well. We can assume which lime he meant based on the description as well as where in the world he happened to be. Baker’s Bumble Bee cocktail, a honey-sweetened rum sour, was published in the South American Gentleman’s Companion in 1951, and would have most likely been made with Key limes according to the regional availability.

When I learned of this history, I thought it must certainly impact modern cocktails based on early 20th-century recipes. If a drink calls for an ounce of lime juice, and we use Persian limes when the author intends us to use Key limes, the drink will surely be altered.

I set out to test this theory with as few ingredients as possible, so as not to detract from the limes. A daiquiri is the perfect subject: lime juice, simple syrup and rum. For this test, I mixed two daiquiris with the same proportions, one with each lime. The Key lime daiquiri resulted in an almost cloying drink. After a bit of research, I discovered Key limes are slightly more acidic than Persian limes, which one would assume requires a greater amount of sugar to balance potential mouth-puckering sourness. However, Key limes’ distinctive aroma is often perceived as sweet (in the same way aromatically “sweet” ingredients like vanilla, strawberries or bone-dry Austrian Riesling might be perceived to taste sweeter regardless of actual sugar content), meaning a balanced drink using Key lime juice actually requires less sugar.

Once I understood the way each juice behaved in its respective daiquiri, I was able to adjust and make a balanced version of each. Due to the lower acidity of Persian limes and more subtle aromatic compounds, I prefer to increase the amounts of juice and sugar. My daiquiri specs are relatively dry and can be adjusted up or down depending upon what tastes good to you, but as Baker begs us, “Remember please, that a too-sweet daiquiri is like a lovely lady with too much perfume.”