I’ve recently come across a lot of information and misinformation about 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.
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. 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. Let’s clear this up first: the USDA does not have a recommended procedure for canning butter at home. This is not because they have ulterior motives. It is simply because they have not created and tested a procedure which they can reliably claim to be safe. And if they can’t reliably claim a procedure to be safe, then they won’t recommend it.
This may lead you to ask why the USDA has not done the legwork to create and test such a procedure. On this, I can only speculate. Perhaps it is because of a lack of funding to the department(s) responsible. 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. Again, I can only speculate on their reasoning, and such speculation distracts us from actual facts.
Now that we have the USDA part out of the way, let’s talk about what butter actually is. Even though I know better, I still find myself constantly surprised at how little people know about butter. It’s constantly referred to as a fat, which is understandable, since fat does make up the bulk of butter’s composition. However, “whole butter” is not 100% fat. It is in fact an emulsion of fat, water, milk solids, and sometimes salt. Depending on who made the butter, usually butterfat makes up somewhere between 80-85% of “whole butter”. American butter tends to have less fat, European butter tends to have more. Milk solids and any salt usually comprises around 1-2%, while the rest is water.
When all of the water and milk solids have been removed, the resulting product is called “clarified butter”. Notice that I didn’t mention salt in this equation. This is just conjecture, but I’m not entirely convinced that clarfying butter will remove 100% of the salt content from salted whole butter. This is irrelevent to me, since I only buy unsalted whole butter (not counting butter spreads), but it may be relevant to you.
Now that we know more about the composition of butter, it’s time to talk about the methods presented for the preservation of butter at home, and why they should concern you.
When you can food at home, you should sanitize the jars that you use, as close as possible to the time that you use them. You should wash them in warm, soapy water and rinse them, at the absolute least. If I were you, I would take it one step further and run your jars through the dishwasher, and let them sit there, with the door closed, until you need them. There are other methods which are suitable, all of which involve steam, but the dishwasher is my preferred method.
What you should never do is heat your jars in the oven. Mason jars are not designed to be heated in the oven, and doing so increases their chance of breakage. The dry heat of the oven also does not adequately sanitize jars. I read one blog post that recommended oven heating jars, on the basis that water inside the jars is undesirable. Remember that butter already has water in it; the residual from sanitizing jars using a wet method will not suddenly contaminate the fat by being water.
With jar sanitation out of the way, we are free to contemplate the actual canning method. According to the USDA, there are plenty of sites that will recommend melted butter into jars and closing them, with no further processing. Somehow I managed to miss any of these sites. Nevertheless, as the USDA tells you, this method is completely unacceptable. Just storing something in a jar is not the same as canning it, and this method does not meet any definition of canning.
One might consider steam-canning as their method of preservation. According to the USDA, the only thing you should ever steam can is juice. Personally, I won’t even do that. As far as I’m concerned, the only thing that steam canners are useful for is sanitizing jars. And as I’ve already said, I don’t even use them for that. If you have one, just throw it away.
Next up is boiling water canning. I did see a number of blogs recommend water bath canning, which is disconcerting to me. Let’s be clear: boiling water canning is only acceptable for high-acid foods. This means that any food with a pH above 4.6 should never be processed in a boiling water canner. Since butter is in the 6.1 to 6.4 range, it should never be processed in a boiling water canner.