The White Russian cocktail has been popular since the mid-20th century. Its creamy texture and sweet flavor make it approachable for those who rarely drink alcohol, and offer an easy, no-frills dessert beverage for more experienced drinkers. Although the White Russian is a very straightforward and simple cocktail, it is not necessarily a foolproof endeavor for the home bartender. Mixing dairy and alcohol can result in an undrinkable mess of curdled milk, but if you understand the science behind the recipe, you will be able to pour the perfect White Russian every time.
Fill the cocktail shaker 3/4 full of ice.
Pour one part half-and-half or heavy cream over the ice. It is crucial to choose a dairy ingredient with enough fat to keep the milk solids emulsified when they are mixed with the alcohol. Milk proteins begin to coagulate, or curdle, when they drop below a pH of 6.5. The fat in the dairy prevents the proteins from coagulating. Low-fat milk is two percent fat, which is not enough to prevent curdling. Half-and-half is 10 percent fat, which is generally enough to slow coagulation, especially if you mix the alcohol and dairy carefully. Heavy cream has up to 40 percent fat, which makes it nearly foolproof when mixing with alcohol.
Add one part coffee liqueur and two parts vodka to the dairy. If you used a lower-fat dairy option such as half-and-half, pour the alcohol slowly and stir constantly with a cocktail stirrer. If you chose full-fat heavy cream, you can simply pour the alcohol into the shaker.
Put the lid on the cocktail shaker and shake vigorously to combine the ingredients.
Strain the cocktail into an old-fashioned glass and serve.