I've been working with raw milk for the past three weeks. As a stepping stone along my path to making aged cheeses, I learned to make cultured butter. The process is ridiculously simple, and the resulting product is delicious enough to eat with a spoon.
In the most basic sense, this is how butter is made, "You agitate a container of cream until the fat globules are damaged and their fat leaks out and comes together into masses large enough to gather." That's from Harold McGee's book On Food And Cooking.
The butter is "cultured" in the sense that native bacteria in raw milk are allowed to ferment the cream a little before churning it into butter. (That's how butter was made in the days before you could order neat little packets of bacterial cultures on the internet.) The fermenting, aging, or ripening of raw cream is accomplished simply by leaving it out at room temperature for a given period of time.
As the cream is aging, a number of things are happening that bestow a fuller flavor and make it easier to churn into butter: bacteria in the milk are converting lactose into lactic acid and producing aromatic compounds - both of which increase the buttery flavor. The lactic acid also helps weaken fat globules so they'll release their contents during churning. Fat crystals are also formed during aging - these lend an additional hand in breaking open globules so the fat can gather into butter. As a recovering scientist myself, I'm skeptical about what I've written above - it's all stuff I read but have not sufficiently tested to say with confidence what I believe is going on at the microscopic level. And by golly, who cares!? All you really want to know is how to make delicious butter at home.
I tried a couple different techniques for churning the aged cream into butter - shaking it in a jar and running it in a food processor. The food processor method was noisy, messy, and overall a less pleasing experience than simply shaking a jar of cream. For this blog posting, I'll only show you how to make butter in a jar.
Mmm...look at all that cream on top of the milk!
I siphoned off the cream.
Two cups of unprocessed cream. This is the same jar I'll use to "churn" the cream into butter. You have to leave plenty of room for expansion.
To "ripen" the cream, I covered the jar with cheesecloth and put in my oven with the light on, overnight. It's too cold in my house otherwise, but it was about 80 degrees in the oven.
The next day, I put the ripened cream in the fridge for maybe an hour and a half. From what I read, cooling the cream before churning helps fat crystals form, which in turn help burst fat globules while churning. However, the first time I made butter (in a food processor) I didn't chill it and it worked out - but I did find myself wishing I'd chilled the cream because the butter seemed so soft as to be close to melting.
After cooling the cream down a bit (but nowhere close to refrigerator temp) I added half a teaspoon of kosher salt to the cream before churning. I don't think this is the right time to salt the cream. It didn't seem to interfere with the process, but it also didn't really end up in the butter. It pretty much separated with the buttermilk.
I put a lid on it in preparation for shaking things up.
I started a timer just to see how long it would take. I started out by shaking in slow, regulated intervals of about 3 shakes per second, but abandoned my restraint after five minutes of nothing happening.
I don't think there's any risk of shaking too fast or too hard. I mean, if you can make butter in a food processor (which I did) you can go crazy with the shaking. Once I really got into it, it only took a couple minutes for the change to begin.
Once the butter starts to form, it goes really fast. Maybe a minute or less of additional shaking.
The butter is ready to be strained at this point.
And if you keep shaking, you won't get any more butter, rather it will start to stick to the sides of the jar. Stop your churning if that starts to happen.
Hey, I made butter! I guess the cow and her lacto bacteria did most of the work.
I lined a strainer with cheesecloth and put it over a pan.
Pour the butter and resultant buttermilk into the strainer.
You could use it now, but I want to drain and compress it. (This is probably the right time to add salt.) It's really soft, so I'm going to chill it for 10 minutes to make it workable.
Into the fridge for a bit.
Once it's chilled a bit, I can press it into a loose ball.
Then I twist the cheesecloth tight around it to really compress it and squeeze out all the liquid.
I put it back in the fridge for at least an hour.
After compressing/chilling: beautiful butter.
I find it hard to believe that this could be unhealthy!