I saw an article about making homemade butter on the Star-Tribune web site a few days ago and decided to give it a try. I didn't get terribly involved and seek out a specific dairy or even a dairy per se but just bought a couple pints of heavy cream (without carrageenan which would make the buttermilk froth. Curiously the stuff in the organic section had this. I know it's natural or naturally derived, but it still seems odd.) I did not bother souring the cream (letting it sit out for some time) but just started right in.
Making butter is simple enough: beat the cream the same way to make whipped cream and then just keep on going. Simple doesn't mean that that is all. Once made, it has to be separated from the byproduct: buttermilk. Simply kneading the butter forces the milk off and most can just be poured off - and into a jar for later use. This takes a while and is a bit messy. Once as much buttermilk as possible has been reasonably extracted, the butter is "washed." Cold water is added and the kneading continues and the water is drained off - not into the jar, but down the sink. This is repeated until the water stays clear. Then there is both butter and buttermilk.
The butter is simple and if salt is desired it will need to be added - probably just after the buttermilk is poured off. I think the result is sweeter than regular store-bought butter but I don't really notice the difference on bread (another reason I made that beer bread: to test the butter). I did try a side-by-side comparison and found that there is no difference, for me, big enough to justify going out of my way for this very often. I'm not saying there is no difference. I am saying that I do not taste enough of a difference to consider this more than a novelty project.
The buttermilk is nothing like the "cultured buttermilk" commonly sold. It's lighter. It isn't weirdly, sickly thick. It doesn't smell spoiled. jmaynard complained that it was just regular milk and found it lacking. I found it a tremendous improvement. I would like to try some commercial "churn buttermilk" sometime if we can ever find any. I think it would be good to compare that with what I wound up with and with the cultured stuff. It's possible that had I let the cream sour the results might have been different. I might give that a try sometime, but I'm in no hurry.