How to Make Hot Chocolate for a Crowd

The ratio per cup

Our classic American hot cocoa follows Hershey's recipe: 1/4 cup cocoa, 1/2 cup sugar and 1/3 cup hot water to a quart of milk, for six 6-ounce servings. Per cup of milk, that is 1 tablespoon of cocoa and 2 tablespoons of sugar. Hershey's own crowd version is a little darker and less sweet: 1 1/4 cups cocoa and 1 1/2 cups sugar to a gallon of milk, for 22 servings of 6 ounces, or about 1 1/4 tablespoons of cocoa and 1 1/2 of sugar per cup.

By our arithmetic, 12 big 8-ounce mugs need 12 cups (3 quarts) of milk, 3/4 cup cocoa, 1 1/2 cups sugar and 1 cup of hot water for the syrup at the small-batch ratio. A jar of homemade hot cocoa mix works too: America's Test Kitchen (ATK) stirs 1/3 cup of mix into each cup of hot milk.

On the stove, without scorching

Hershey's crowd recipe uses a 6-quart saucepan: stir the sugar, cocoa and salt together, add the water and boil the syrup 2 minutes, stirring constantly. Then add the milk and heat it to serving temperature, stirring often. Do not let it boil. Stir in the vanilla off the heat.

Milk scorches because its proteins settle and stick. The Exploratorium's science of cooking pages say milk proteins tend to scorch once they come out of solution, which is why milk is best heated gently. ATK tested ways to keep milk from sticking: a pan misted with vegetable oil spray, or swirled with a little water, came out almost clean, while stirring every 2 minutes made little difference. Use a heavy pot, moderate heat and patience.

In a slow cooker

The fastest route is ATK's: make it on the stove, then move it to a slow cooker on low to keep it warm. The slow cooker can also do all the work. The University of Missouri's hot chocolate bar recipe combines cocoa, 20 ounces of chopped chocolate, 10 cups of whole milk and a can of evaporated milk in the slow cooker for 4 hours on high or 6 on low, stirring every hour so the chocolate doesn't settle on the bottom.

USDA's Food Safety and Inspection Service (FSIS) says hot food held for serving should stay at 140°F or above, in a slow cooker that is already hot. Leftovers go in the refrigerator within 2 hours; FSIS does not recommend reheating them in the slow cooker, so warm them on the stove first.

Stopping the skin

ATK explains the skin on hot dairy: as the mixture heats, water evaporates from the surface and the proteins and sugar there become concentrated into a film. Anything that stops evaporation helps, which is why ATK presses parchment onto puddings.

For a pot of cocoa, that means keeping the slow cooker lid on between refills and whisking before you ladle, which also brings back the foam Hershey's whisks up at the end. Not boiling it helps too. Set out toppings and more mugs, and find other styles in our hot chocolate hub.

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