If you take a trip to Chile or Peru, you'll find that the Pisco Sour is a massively popular drink. It's so popular in both countries that each has designated it as their official drink. Moreover, both Chile and Peru claim that they are the birthplace of the Pisco Sour.
What is pisco, you ask? It's a grape-based brandy that comes from winemaking regions in Chile and Peru. It's quite a distinctive product. The color is usually much lighter than other brandies, and the flavor has a sharp note akin to grappa or other grape-based eau de vie.
Because of pisco's unique nature, there isn't much of anything you can use as a substitute. Besides, if you did subsitute something, you drink wouldn't be a Pisco Sour anymore, would it?
There wasn't much to the creation of the drink. The sour cocktail was (and is to this day) one of the more popular drink styles. All it took was for someone to bring the sour from its US roots to South America, where it was made using the local spirits. From there, it's become one of the most popular cocktails in South America.
See also: How to Make an Earl Grey Mar-Tea-Ni
As you could imagine, a Pisco Sour isn't too far off from any other sour cocktail that you've made. However, there are two things that make it a little more distinct.
First up is that the recipe calls for the use of egg white. This is something you can do to improve any sour cocktail. It gives more body to the drink, and creates an attractive foamy head. While the "proper" way to incorporate egg white is to do a dry shake (shaking everything together without ice), I more often cheat and give everything a buzz with a stick blender or milkshake machine.
Second is the Pisco Sour's unique use of Angostura bitters. Bitters are often used to add complexity to a drink. In the case of the Pisco Sour, Angostura's aromatic qualities are emphasized by putting a few dashes on top of the egg white foam. When you take a sip of the drink, you get a good sniff of the bitters, giving a different character than just mixing in the Angostura like you would on most other drinks.
Pisco Sour 1-1/2 ounces pisco 1/2 ounce lime juice 1/2 ounce simple syrup Half an egg white Angostura bitters for garnish
Shake pisco, lime, syrup, and egg white very hard for 30 seconds in a shaker without ice. Add ice and shake hard until well chilled. Strain into a chilled champagne flute or Old-Fashioned glass. Dash a few drops of bitters on top of the drink.
