Butterfat is the term used to describe the fat content that occurs in milk naturally.
It’s what gives dairy products their body, structure, mouth feel and richness of texture. It’s a difficult fat to “fake” because it’s actually made up of a bunch of different fats, or “tryglycerides”, to be more precise, that have their own melting ranges ranging from -40 C to plus 40 C.
Milk, cream and butter are usually classed based on the amount of butterfat they contain.
Butterfat is the most expensive component in dairy products. In dairy products, most manufacturers will aim to provide the lowest amount of Butterfat that they can use and still be allowed by law to call a product by a certain name.
You can collect the Butterfat out of milk by churning the milk, which causes the Butterfat to coagulate and separate out.
In cooking, the higher the Butterfat content in a cream being used, the less likely the cream is to separate.
In the 1990s, dairy producers began experiencing something they hadn’t before in history: a glut of Butterfat as a new generation didn’t want the butterfat content. They wanted low-fat or fat-free dairy products. At the same time, the milk industry was predicated on paying milk producers based on the butterfat content on the milk: the more butterfat, the more money. But Americans had the problem that they couldn’t sell their Butterfat abroad, because on the international market their price would be one of the highest, and therefore least competitive.