In the course of a busy shift, a craft bartender may make drinks from 40 to 50 different recipes. To be efficient, some bartenders may have dozens—if not hundreds—of recipes memorized, but most bartenders don’t have time to commit all that information to memory.

Instead, they focus on templates. For example, the Whiskey Sour, Margarita, Gimlet, and Daiquiri all follow what’s called the "golden ratio" of cocktails—2:1:1, meaning made from two parts liquor, one part sweetener, and one part sour. This formula is the basis for many other kinds of drinks as well. For example, substitute lemon juice for lime juice in a Gimlet and add soda to make a Tom Collins. Swap the soda for champagne and, voila, it’s a French 75.

Punch This

All of these cocktails follow the formula for a traditional sour: booze, a sweetening agent, and a souring agent. This, along with most other genres of cocktails containing fruit, was born from the tradition of making punch.

From about the mid-1600s to the mid-1800s, punch ruled the drinking scene. Instead of sipping on a single serving of your favorite beverage, you’d split a bowl with a group of friends. At the time, it was usually a mixture of liqueur, spirits, water, and locally available spices and fruits. Later, if you could afford it, it also included a block of ice.

Interestingly enough, the rhyme most associated with punch (“One of sour/Two of sweet/Three of strong/Four of weak”) doesn’t match up with the golden ratio. This discrepancy is probably due to a few things including regional differences in punch-making as well as the variations in dilution and consistency between punch and cocktails.

Right In The Glass

During the mid-1800s the drinking scene became more individualistic, and the quickly quaffed cocktail gained steam. The sour was likely preceded by a very simple punch. It’s likely that this format also got a boost from bartenders trying to cover up foul-tasting spirits during Prohibition.

Whatever the cause, the golden ratio became prevalent. Although stirred cocktails have a couple similar templates, none of them is quite as ubiquitous as the 2:1:1 of the shaken sour.

Hit The Lab

The golden ratio is also an easy way to formulate cocktails at home. Start with two ounces of a base spirit, add one ounce of simple syrup, then choose a citrus juice that compliments the booze and add one ounce of that. Shake with ice, strain, and add your garnish of choice.

But this ratio isn’t for everyone. If it’s too sweet, try 3/4 ounce of sweetener. If you want some more depth, substitute your favorite liqueur for the sweetener. Too boozy? Add a splash of soda water or your favorite sparkly beverage. If you think that might thin the texture out too much, use a thicker syrup such as gomme syrup, or add an egg white.

If you want to get really fancy, add a dash of bitters for depth. You can also use two bases, juices, or sweeteners—just cut the amount of each that you use in half. Or, rinse the glass with absinthe or spray it with aromatic water. You can also muddle fruit or herbs for a seasonal twist.

For tasting's sake, just change one ingredient at a time. Start with simple syrup, citrus juice, and the base spirit, and work from there. Make notes on what you like (or don’t) so you can tweak the recipe a little bit at a time. When you put something together that you like, Google the ingredients list. This formula has been used so often it’s likely that you’ve stumbled upon a drink that’s been made before. If not, name it yourself!