Why Do Stick Margarine and Spreadable Margarine Behave Differently in Cooking?

Margarine is a mixture made by combining vegetable oils with water and dairy products, and its fat content varies considerably by product. Stick margarine sold in blocks has a high fat content and a firm texture when refrigerated. Spreadable margarine sold in tubs is easy to spread even straight from the refrigerator; this softness comes in part from its higher water content. Products sold as light margarine contain even more water.

The difference is immediately apparent in a pan. When margarine with a high water content heats up, its water evaporates; the margarine foams, sizzles, and splatters. Because there is less actual fat in the pan at that point, food sticks to the pan instead of browning. Eggs, vegetables, or meat fried in it do not develop the expected crust. Stick margarine contains more fat, so it splatters less and is better for frying, but, like butter, it also contains milk solids and browns at high heat.

The result also affects the texture of baked goods. In doughs for cookies and savory rolls, fat coats the flour particles, limits gluten development, and separates layers. Margarine with a high water content cannot do this: it adds extra liquid to the dough, gluten develops, and cookies spread on the pan and become tough. In layered dough, water moistens the dough instead of evaporating to separate the layers. That is why baking recipes use stick margarine or butter, and both should be kept cold.

Reading the label removes the guesswork. The fat content is listed as a percentage on the package; the higher it is, the more suitable the product is for cooking. Butter has a similar fat content, so the two can often substitute for one another in recipes. Specialty margarine sold for pastry-making has an even higher fat content, and its melting point is adjusted for layered dough. If you make a recipe with a lower-fat product, reduce the added liquid, but the result still will not be exactly the same.

Storage and use also differ. Margarines with a high water content should be kept refrigerated in a closed container after opening; an uncovered tub absorbs odors and its surface hardens. Stick margarine keeps for weeks in the refrigerator and months in the freezer. As with butter, a sharp, rancid smell indicates that margarine has spoiled. For frying, use margarine together with a liquid oil that can withstand high heat, not on its own. Thaw frozen margarine in the refrigerator, and do not refreeze it.