Margaritas, Gimlets, and Cosmopolitans Are All Sours—Here's Why This Classic Cocktail Style Is Having a Moment

A sour is an iconic type of cocktail. Even if you don't realize it, you've probably had one before, as classics like the daiquiri, margarita, and Cosmopolitan are all sour cocktails. Though it sounds unpleasantly puckery, a sour has a well-balanced ratio—it's a time-honored combination that continues to work. The sour is having a renaissance right now, so we're digging into the origins and applications of a much-loved, but perhaps under-appreciated type of drink with the help of cocktail professionals.

What Is a Sour Cocktail?

A sour has just three base ingredients: liquor, citrus (the "sour" part), and sweetener. The combinations of these ingredients are endless: a sour can be made with any spirit, but most commonly with whiskey, tequila, gin, rum, or vodka. The citrus element is usually lemon or lime juice, but many variations feature grapefruit, orange, tangerine, or even less common iterations, like yuzu. As for the sweetener? Sugar or simple syrup is the typical sweet element, but syrups made from agave or honey and sweet liqueurs like triple sec are also sometimes used.

Remember that sour ingredients are necessary to balance sweet elements of your drink. "Our taste buds have a limit on how sweet a drink can be—when something is too sweet, it can be cloying and unpleasant. In sour drinks, the sugar becomes a canvas for the citrus and alcohol, letting the notes of the drink be showcased," says Tony Jimenez, bartender at Philadelphia cocktail bar 1 Tippling Place.

A Little History

Legend has it that the roots of this flavor combination go back to the 1700s, when sailors often had bouts of scurvy due to vitamin C deficiency while at sea. When it was discovered that citrus could help prevent scurvy, the British Royal Navy added lemons and limes to their ration kits (earning these sailors the nickname 'Limeys'). It didn't take long for these sailors to discover that their citrus was, in fact, delicious with the rum and sugarcane they'd consume as they sailed through the Caribbean.

The (Optional) Fourth Ingredient

An egg white is an often used optional addition to the main three ingredients. Egg whites give a cocktail a velvety texture and a pretty froth of foam on top. Nearly all eggs at grocery stores in the United States are pasteurized and safe to consume. An alternative to egg whites that many bartenders use is aquafaba, the liquid in a can of chickpeas. It's an excellent alternative if you're vegan or prefer not to ingest uncooked egg whites.

Classic Sour Cocktails

You may have heard of the whiskey sour or the pisco sour. But, some of the most classic cocktails of all time are, in fact, sours by another name. You may already be ordering them at happy hour:

• Margaritas
• Mojitos
• Cosmopolitans
• Sidecars
• Lemon drops
• Gimlets
• Palomas
• Daiquiris

Not only will citrus make a sweet drink more palatable, but it can also elevate and showcase the depth and complexity of the liquor of your choice. "It celebrates your chosen base spirit—whiskey, for example, while hitting that perfect balance with fresh citrus and your sweet element," says Robin Wolf, owner of cocktail bar Highwater SLO in San Luis Obispo, Calif.

And the classic sour cocktails don't stop at just the core three components—many of them bring in additional ones to create a range of flavor profiles. Anyone who loves to cook understands how a little salt or lemon juice can transform a dish; in mixology, the same principles apply. The sour is the best canvas: "A sour is the best cocktail to begin understanding how ingredients play together. Adjust the ratio of citrus to sweetener, introduce a flavored syrup, add a lengthener like soda or sparkling wine, swap out one base spirit for another, or split the base spirit. Any one of those adjustments will teach you so much about cocktails and ingredients. It's the best starting point," says Beth Serowsky, lead bartender at Chicago cocktail bar Meadowlark.

Why Sours Are So Popular Right Now

Cocktails are currently being ordered at a rapid pace in bars and restaurants across the country—and there are a lot of sour drinks in the mix. "More cocktails always mean more sours," says Jimenez. One reason is that after a couple of years of staying at home, where most of us found it simplest to open a bottle of wine or a beer, we're now craving the delicious concoctions a professional bartender creates.

Jimenez also credits the rise in "ready to drink" cocktails (aka RTDs, which are pre-mixed in bottles or cans), to an increase in cocktail orders at the bar: "Now that quality highball RTDs are easily accessible to the guest, they venture out more when they go out."

New Sour Variations to Try

This year, expect the sour variations served at your favorite cocktail bars to get even more creative. "Adding an amaro or making a fun syrup using fresh fruit, vegetables, and herbs from the farmer's market is a great way to explore new flavors. A sour is also a great format for creating delicious low-ABV cocktails," says Serowsky. "Using sherry or vermouth as the main base while using traditional base spirits like rum or brandy as a modifier ingredient is not only delicious, but a game changer for responsible drinking."

Looking for fun, different sour cocktails to try? Wolf recommends ordering an Aviation Sour—a play on the classic Aviation cocktail made of gin, maraschino liqueur, and creme de violette, turned into a sour. "Everything that makes the classic cocktail a fan favorite shines through with the addition of egg whites. Bright, floral, and seriously aromatic, the lavender color even gets a pop with the meringue of the egg," she says. She also recommends simply adding a spoonful of jam to your cocktail shaker: raspberry, peach, and blackberry are all great options.

5 More Sour Cocktails to Order

• Nuyorican Sour: rye, rum, lime, sugar, egg white, with a Spanish wine float
• Southside: gin, lemon juice, simple syrup, and fresh mint
• New York Sour: whiskey, lemon juice, simple syrup, and egg white, with a red wine float
• Bees Knees: gin, lemon juice, honey
• Stone Sour: any sour recipe with the addition of a splash of orange juice (this adds additional sweetness and helps mellow out the profile of a sour)