Science With Franny -- Butter

So she got me again last night. I'm falling asleep and I hear "What IS butter?" "It's fat Franny. Good night." "But how is it made?" "Are you serious? Alright..."

Butter is mainly fat. It also has some water and other milk remnants, proteins and such. Some milk is sold as is straight from the cow, although usually pasteurized first. However, most dairies separate the cream out first. The result is sweet cream, which is ~35-40% fat, and skim milk. Some of the cream is then added back in in whatever amount needed to produce the proper blend (1%, 2%, or whole, about 4%) for the grocery store. This is more exact than trying to take out just a certain part of the fat in the original milk. Therefore the final product is more uniform and the American consumer does not have to be distressed by inconsistency. The rest of the cream can then used to make butter. It is somewhat processed (pasturized and then cooled), and then churned. This mainly breaks up the fat globules and makes them stick together better. It also works out most of the remaining water. In an industrial process, this might be done under a nitrogen environment to help prevent rancidity during the process, which allows for larger batches at a time, but doesn't mean much to the end product. The cream has now been separated into solids (the butter) and liquid (buttermilk), which are sent on their separate ways. Depending on the desired product, other things might be mixed in at this point, such as salt, preservatives, or colorings (to get that particular Land-O-Lakes yellow or whatever).

There you have it. Where butter comes from. The cream might also be used for other things like ice cream (excellent use), or the whole milk might be used for cheese or yogurt or whatever instead.