I gave up on butter when it gave me lumps on knee. I wear an artificial leg. I was using grass fed frozen raw butter from a farmer I researched and found in Wisconsin. It was made at the height of his green grass growing season. Since having experimented with frozen back fat, and subsequently noticing a sizable drop in energy over eating fresh back fat, I am inclined to think it may have been the frozen element in the butter that allowed something to coagulate into a lump, repeatedly, testing out the frozen butter. I also since the 70's have developed similar lumps when trying to take oral mineral supplements. Have you ever seen where they show video from a microscope of single blood cells getting bottlenecked running through a capillary. MY theory is since I wasn't breast fed, according to lit., I have more of a porous intestinal lining, allowing for larger particles to enter my system. I would love to have your source for fresh butter, if grass fed. I love the taste of it, especially eating it with meat.