Okay, I say this with fear and trembling...
cause there is about 1000 year experience reading these comments, but I lived among an Amish community in OH and learned a lot from them about putting food by, even have a lot of their recipes they canned, and one of them that I canned for Y2K was called Mock Cheez Wiz. Canned about 40 pints of it and used it up in 2000 and 2001. It was great and didn't make any of the fam. sick. I'm just saying, I don't know what I'm saying. I'm just saying that I've seen it done, not canning straight butter mind you, but canning some things that have milk products in it, like the Mock Cheez Wiz, Blueberry Pie Filling, Apple Pie Filling that has Clear-Jell in it. We canned brown rice in quart jars, and it turned out great. When we wanted to use rice, we just opened a jar and it's ready to use.
I don't know, I'm just adding what I've seen done and what I've done myself threw learning from the Amish.
Learning from the Best, y'all....
cleanheart