Cream is one of the most luscious and versatile of natural ingredients, equally at home in sweet or savory recipes. From your cup of coffee to the sauce on an elegant restaurant meal, it brings a concentrated and mouth-pleasing sensation of richness to any food or beverage. Cream is available in liquid or cultured forms for various purposes, varying widely in fat content. For example, heavy and light whipping cream are used similarly, but aren't identical.
There's an old saying that "oil and water don't mix," and generally that's true. If you shake up a vinaigrette, its oil and water-based vinegar will mingle temporarily, then separate. Mayonnaise adds an egg yolk to those basic ingredients, which helps them form a stable and non-separating mixture called an emulsion. Cream is also an emulsion, combining butterfat with relatively watery whey and its proteins. It naturally separates from warm milk, another emulsion, just as the fat rises to the top in a cup of gravy. Commercial creams contain varying amounts of fat, depending on how completely they've been separated from the milk.
If you boil milk, it's prone to separating into thin whey and small, grainy curds of protein. That's because protein accounts for about half of milk's weight. In cream, as the percentage of fat increases, its character changes. Half-and-half, at approximately 12 to 18 percent, is essentially a thick milk that adds richness to coffee or cereal. If cooked, it will still curdle in the same way as milk. When the fat content in cream reaches 30 percent or higher, it contains almost 10 times as much fat as protein. That means it's stable when cooked, and can be whipped into a light, long-lasting foam.
Light Whipping Cream
Light whipping cream averages 30 to 36 percent milk fat, varying between brands and regions of the country. Its fat content is high enough to make it well-suited for use in sauces, custards, cream soups and other recipes that require heating. It will also whip into the light, familiar whipped cream used as a dessert topping or garnish. However, because its fat content is lower than heavy cream, the foam isn't as stable. It's fine for immediate use at home, but bakeries seldom use it because it soon begins to deflate and leak liquid cream if it's used on cakes or pastries.
Heavy Whipping Cream
Heavy whipping cream typically averages 38 to 40 percent fat, a small but significant difference. Whipped cream holds its shape because the whisk physically shears the globules of fat, causing them to realign and form walls surrounding the air bubbles left behind in the cream. With its higher fat content, heavy cream whips more quickly and forms a foam that is more resistant to deflating over time. That's why bakers and pastry chefs prefer to work with heavy whipping cream.