Caramel 101

• When table sugar is heated to a temperature of 340 degrees Fahrenheit or higher, it begins to change dramatically. The sucrose molecules break down into hundreds of smaller fragments, creating a startling range of complex flavors out of the bland sweetness of the original sugar. This process also gives the caramel its distinctively deep golden color. Professional pastry chefs sometimes simply heat the dry sugar, but recipes for amateurs usually call for water to be added. The water boils away as the sugar heats, but makes it easier to bring the sugar to the right temperature without scorching it.

Caramel Sauce

• Caramelized sugar cools to a hard and brittle consistency, which limits its usefulness. To turn it into a sauce, it must be diluted until it reaches the appropriate consistency. Adding water creates a thin, clear sauce. Richer sauces use cream, butter or both, and sometimes add vanilla for even more depth of flavor. The high fat content of the butter and cream keeps them from curdling when they hit the hot sugar, though much of their water content boils away in the first few seconds.

Caramel and Milk

• Fat content is the reason that milk is a poor substitute for cream in a caramel sauce. While heavy cream can be as high as 40 percent fat, whole milk is usually only 3.25 percent fat. When the milk is added to the hot sugar, the extreme heat causes its proteins to contract and form hard curds. The result is a watery sauce, speckled unattractively with the equivalent of fine cottage cheese. For cooks who want to make caramel sauce but have no heavy cream on hand, there are alternative substitutions.

Alternatives

• Evaporated milk can be used as a direct replacement for cream in caramel sauce, because it's already concentrated enough to resist the curdling effect of the sugar's heat. It adds a slightly "cooked" flavor to the sauce, but the overall effect is not unpleasant. A usable sauce can also be made using just butter, though it's very rich and can become chewy as it cools. If milk is your only alternative, pour the caramelized sugar onto an oiled or parchment-lined sheet pan and let it cool. Then, break up the caramel into small fragments and stir them into hot milk. Stir constantly until the caramel is dissolved, then let the milk simmer until it reaches a suitably thick consistency.