Antiquated as it may sound to contemporary ears, oleo saccharum isn’t all that ancient. Its name is Latin for “oil sugar,” but a Roman citizen would have no earthly clue what it’s used for. Instead, you’d have to ask a bartender, who would probably abbreviate it as just “oleo” and start going on about Jerry Thomas and other cocktail arcana. They’d explain that it’s a critical flavoring component of classic punches—as old as cocktail culture itself, really, but not quite as old as Pliny the Elder. And it’s nothing more than a syrup made of citrus peels and sugar.
Many sources claim that the first mention of oleo saccharum was in 1670, when Hannah Woolley’s recipe for Limonado called for lemon “pill” to be “brewed together” with sugar and other punch-like ingredients, but it wasn’t until the 19th century that we find a cocktail book describing a method for making it. Richard Cook’s Oxford Night Caps, published in 1827, includes several recipes for punch, calling for the reader to “extract the juice from the peeling of a lemon, by rubbing loaf sugar on it.” And then Thomas, the so-called “father of American mixology,” popularized it in his canonical Bar-Tender’s Guide edition from 1862, which includes instructions to “rub the sugar over the lemons until it has absorbed all the yellow part of the skins.”
What does oleo saccharum add to a drink?
If you’ve never heard of oleo before, you might wonder why anyone would go to the trouble of rubbing a loaf of sugar on a lemon when you could just squeeze the damn juice and mix it with some sweetener. A fair question! But the compounds found in the fruit are different from what’s trapped inside the orange and yellow skins.
What we typically call the peel or rind of citrus fruit is made up of the epicarp (also called the flavedo) and the mesocarp (also known as the albedo). The flavedo is the zesty part—the outermost layer of the fruit that’s full of tiny, flavor-packed oil glands—while the albedo is the bitter, spongy layer commonly referred to as the pith. The juice contained in the vesicles beneath the peel have a different chemical composition than the essential oils in the flavedo, resulting in a different bouquet of volatile organic compounds (though both are quite high in limonene, one of the most common terpenes in nature). This variance in composition means that citrus oils can have more floral and herbal characteristics than the fresh, tangy flavors found in citrus juice.
If you’ve ever made a martini with a lemon twist, you probably understand the concept already. Twisting a lemon peel over a cocktail bursts those teensy flavedo glands, releasing a fine mist of concentrated essential oils over the surface of the drink. It won’t taste sour or lemonade-ish, as it would if you’d added lemon juice; instead, the twist adds a suggestion of citrus rather than a command. (Muddling a peel accomplishes the same thing, while flaming a twist alters the character of the oils.)
When you make oleo saccharum, you’re trying to extract as much of those oils as possible through maceration. By putting sugar into contact with citrus peels, you’ll draw out their oils, creating a highly aromatic syrup in the process.
How do you make oleo saccharum?
While oleo saccharum is classically made with lemon peels, any type of citrus will work—and a combination of citrus can be just dandy, too. (And be sure to use only the zesty flavedo, as the pithy albedo will turn the syrup bitter.) You can certainly use peels you’ve saved and frozen if you’re the kind of person who does that, but fresh citrus is your best bet, as you won’t have to worry about freezer burn off-flavors polluting your oleo. Just be sure to use unwaxed citrus, or remove the wax by gently washing the fruit with warm water.
Confoundingly for perfectionists, there’s no consensus on the optimal sugar-to-peel ratio for oleo. One recipe may call for the peels of 12 lemons per pound of sugar, while another suggests a ratio of six ounces of sugar for every four lemons. (Generally speaking, more citrus per ounce of sugar will produce more potent oleo, but you do eventually reach a point of diminishing returns.) Personally, I usually stick with Bon Appetit’s recipe, which combines a half-cup of sugar with the zest of four lemons and eight clementines and reliably works with a variety of cocktails.
Beyond citrus peels and sugar, the third ingredient in oleo saccharum is time. The simplest way to make oleo saccharum is to simply combine the sugar and peels in a bowl or mason jar and let the process of maceration do its thing—for an hour at minimum, but leaving it overnight will produce more syrup. Some bartenders suggest shaking, gently stirring, or pressing on the peels during this time to mechanically extract even more of the essential oils.
In The Bar Book, Jeffrey Morgenthaler goes one step further by vacuum-sealing the peels with sugar. Though slightly more complicated than old-school methods, this technique has a few advantages. Under vacuum, the glands in the peels more readily give up their oils, and without any air in the bag, the sugar will always be in direct contact with the peels, further expediting the process. It also means you don’t need to muddle or massage anything—you can just stick the bag in the fridge for four hours, or up to a month.
If you do keep your oleo low-tech—storing it in a glass container is always a safe bet, but a regular zip-top plastic bag will also work—it’s generally prudent to stick to a one-week shelf-life rule, and always store it in the refrigerator. (Although, as Aaron Goldfarb has pointed out, many cocktail syrups can last a long time in the fridge—but look out for cloudiness, which can signal bacterial contamination.) When it’s time to use your oleo, simply strain out the peels, pressing on them to release the last of their essential oils before bottling or adding to cocktails.
Is there any shortcut to oleo saccharum?
It’s not an exact swap, but if you don’t have time to wait for citrus peels to offer up their oils in a sugary bath, you can get some of that fragrance and flavor into a shaken drink through a process called the “regal shake”—simply adding the peels to a cocktail shaker, along with any sweetener, the way it’s done in this Amaretto Sour recipe. Not shaking each drink on its own? If you’re putting together a last-minute punch, you could shake some rich simple syrup with citrus peels for a cheater’s oleo if you don’t mind a slightly fussy extra step.
How can you use oleo saccharum?
If you’re making oleo saccharum, you’re most likely doing it because you found a delicious punch recipe that calls for it. But oleo is incredibly versatile, and you can use it as you would any other flavored syrup. You can experiment with swapping out simple syrup in your favorite cocktail or punch with oleo, but you can also use it in low- and non-alcoholic drinks like lemonade, iced tea, or a Lemon, Lime, and Bitters. Go beyond beverages, too! Drizzle it over ice cream or soak a lemony cake with oleo to keep it moist.
So go ahead and make some oleo. It’ll cut down on your kitchen waste and transform it into something delicious, and you’ll get to brush up on your Latin in the process.
