Cola and diet cola: Mix with anything. Most bars choose either Coke or Pepsi products, but local favorites like RC are getting some shelf space.
Ginger ale: Familiar brands include Canada Dry, Vernors, and Schweppes.
Juice: Common cocktail juices include tomato, orange, pineapple, cranberry, grapefruit, cream of coconut, lime juice or Rose’s Lime Juice, and lemon juice or sweet and sour mix. Some purists, like coauthor Heather, suggest fresh-squeezed juice; of course, it’s better, but much more expensive.
Lemon-lime beverages: Familiar brands include 7-Up, Sprite, and Sierra Mist.
Milk or cream: Several common cocktails (like toasted almonds and white Russians) require milk, half-and-half, or cream. Keep a pint of vanilla ice cream behind the bar for very creamy cocktails.
Tonic water: Some bars keep both tonic and diet tonic in stock
Bitters: For use in Manhattans, Old Fashioneds, and other cocktails that call for bitters or for cocktails you want to add a little bitter flavor to. Consider having a flavored bitters on hand as well, such as orange.
Many small batch craft bitters are being produced around the country these days. Bittermenshas a great line that includes a mole (with chocolate and cinnamon) and hopped grapefruit bitters. Fee Brothers offers black walnut and mint, among other flavor profiles.
Grenadine: Gives a touch of tart and sweet at the same time. It’s a syrup made from sugar and pomegranate juice that adds a deep red color to cocktails.
Hot sauce: For any cocktail that you want to be a little spicy or hot! (See Tabasco.)
Simple syrup: Gives a touch of sweetness to a cocktail. Simple syrup is a 1:1 (usually) mix of sugar and water. Make your own by heating the water to dissolve all the sugar, and then cooling the syrup.
It lasts for up to a month in the cooler, but some bar owners recommend you make it in quantities that you’ll use within a week. You can also buy syrup already made for you.