Why does milk, cream, yogurt, etc. become rancid if left unrefrigerated, but butter can just freeball in a butter dish for-seemingly-ever and still be safe and edible?

Question

I just don’t get it. I’m sure there’s a very sciency explanation, but it makes no sense to me. I love that it can sit out to be soft and spreadable, but you try that with cream and you’re on the way to a stinky cheese, milk or yogurt you’ve just got a curdled surprise.

So why can butter just sit out and not start to stink or become dangerous to eat?

In: 122

Answer 1

Pure fat, pure sugar, pure vinegar, and pure salt are amazing preservatives. This is why we have salted dried fish, jerky, pickles, jam, and confit available on the shelves. Admittedly, fat preserved items are less popular these days, in part because they’re a bit harder to reliably preserve. Also because the Western world would find it kind of gross. Sardines are a common example.

Butter is sufficiently high fat to be reasonably well preserved. Add salt to the butter and it will be even better preserved. Reduce the water content for even longer preservation. Ghee, which is butter with the milk sugars, proteins, and water removed, is almost 100% fat, and is shelf stable for months.