Ice to a bartender is like fire for a chef: The amount and type you use will affect the outcome of the final product. Let’s talk about the main types of ice bartenders tend to use.
Large format or block cubes: These are used for chilling a drink without adding much dilution, like with a whiskey on the rocks or a bowl full of punch. The larger surface area means the ice will melt at a slower rate.
Cubed: The most common ice, usually a half-inch to 1″ in size. This ice can be used for a wide range of purposes, but is ideal for cocktail mixing.
Cracked: Ice cubes that have been cracked into smaller pebbles to increase the amount of dilution they add to a drink.
Crushed: Ice that has been pulverized and has the texture of coarse snow. When ice cubes have been smashed completely (with either a mallet or a blender), it has the highest dilution rate. This ice is ideal for watering down sugar or booziness in drinks like juleps or tiki cocktails.
But when do you shake and when do you stir? If the cocktail is all spirits (and sometimes a syrup), stir for about 15 to 20 seconds with cubed ice (don’t crack it!) until a chill develops on the glass. A Manhattan, for example, is just whiskey, sweet vermouth and bitters. If you were to shake this cocktail, the final product will be thin and watery and the subtleties of the whiskey you chose will be rendered moot.
When a cocktail has juice or egg whites added to it, it’s best to shake well with cubed ice for about 10 to 12 seconds and double strain it. Shaking not only helps emulsify the ingredients (try stirring an egg white cocktail and not grossing yourself out), it quickly brings the cocktail to -7 degrees Celsius, below the freezing point of water and almost halfway to the freezing point of (some) alcohol. This translates to a silky smooth and refreshing mouthfeel.
At the end of the day, just remember: Your cocktail is only as good as your worst ingredient.—Christian Johnston