Milk solids and any salt usually comprises around 1-2%, while the rest is water. American butter tends to have less fat, European butter tends to have more. Depending on who made the butter, usually butterfat makes up somewhere between 80-85% of “whole butter”. It is in fact an emulsion of fat, water, milk solids, and sometimes salt. It’s constantly referred to as a fat, which is understandable, since fat does make up the bulk of butter’s composition. Even though I know better, I still find myself constantly surprised at how little people know about butter. Now that we have the USDA part out of the way, let’s talk about what butter actually is. Again, I can only speculate on their reasoning, and such speculation distracts us from actual facts. Perhaps they have in fact spent countless hours in development and have discovered that with the equipment available to the home canner, such a procedure is not possible. Perhaps it is because of a lack of funding to the department(s) responsible. This may lead you to ask why the USDA has not done the legwork to create and test such a procedure. And if they can’t reliably claim a procedure to be safe, then they won’t recommend it. It is simply because they have not created and tested a procedure which they can reliably claim to be safe. This is not because they have ulterior motives. Let’s clear this up first: the USDA does not have a recommended procedure for canning butter at home. The reasons stated are many, and there is an abundance of misinterpretation of the statements made by the USDA, even by those who directly quote it. If you’ve read any of the articles or blog posts out there, then you probably already know that the USDA does not recommend canning butter at home. Because of the level of controversy, and the amount of unsafe advice out there, I wanted to set a few things straight. I’ve recently come across a lot of information and misinformation about canning butter at home.