Butter and margarine are certainly very similar products—they often look alike and you can often use them interchangeably—but the differences that exist between them are critical.
What is butter?
Butter is a dairy product made from milk or cream. It’s created when cream is vigorously churned, which causes its solids (butterfat) and liquids (buttermilk) to separate, and ultimately results in the firm product we all know and love. Whether it’s salted or unsalted, the flavor of good butter is second to none, and because of its basic ingredients and straightforward processing, it can easily be made at home. Butter must be at least 80% fat to be sold commercially, and the remaining percentage consists of water and milk proteins.
What is margarine?
Margarine, on the other hand, is made from oil, water, salt, and a few additional ingredients such as emulsifiers. It’s flavored to taste like butter (did you know there was a time when coloring margarine to match butter was outlawed in some states?), but usually contains no dairy products at all. Margarine is formed through a complicated chemical process and is therefore not something you can make at home. By law, it must also be at least 80% fat, though manufacturers can get away with less by calling their product a “spread.”
The key difference
It all comes down to the kind of fat involved. As an animal product, butter has high levels of cholesterol and saturated fats that aren’t present in margarine. Margarine, on the other hand, has more polyunsaturated and monounsaturated fats (the good kinds!) but also often contains trans fats (the very bad kind!). Their respective compositions explain why butter is so much firmer than margarine at room temperature—the saturated fats make tightly packed bonds that stay rigid until heat is applied. That’s why you can keep it on the counter.
Though most bakers and cooks prefer butter for its unparalleled taste, margarine does have its place. Because of its high water content, baked goods made with margarine will often have a softer texture. Be wary when trying to make substitutions—many baking recipes from old cookbooks call for margarine, and since those have likely been developed to account for that additional water, it’s probably best to follow them to the letter if you can. Butter is ideal for treats like cookies and frosting, however, since those are recipes where its flavor is important and extra water could be detrimental.
Butter and margarine may have their similarities, but they’re fundamentally different. Knowing how each is best applied will result in more kitchen successes and lots of good eats!