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

The reason is much more simple than most of these comments are positing. The butter has no water in it and doesn’t not absorb water from the air. This concept is why dried foods, honey, pickled, and powered items are shelf stable. Some of them will eventually pull water from the air and start rotting but if they are sealed they are basically good forever. Things will still oxidize though which is what causes things to go rancid. If you remove both water and oxygen you end up with nitrogen sealed freeze dried items which will last for as long as the seal holds and they are kept at a reasonable temperature.