Eli5: why does “good” peanut butter need to be refrigerated?

Question

The only ingredients on the label are “peanuts, salt.”

We keep peanuts unrefrigerated in the pantry… we keep salt unrefrigerated in the pantry… so how come when you mash them together it makes something that (according to the jar) must be refrigerated after opening?

P.S. I put “good” in quotes because all peanut butter is good. What I mean by “good” peanut butter is the healthier stuff that you have to mix the oil back into and there are only the above mentioned ingredients.

In: 2133

Answer 1

To prevent seperation.

Good peanut butter just uses peanut oil, which melts at 37 F, flows, and seperates.

Big brand peanut butters add oils with higher melting points (palm, coconut, or hydrogenated other) which are solid at room temperature and therefore won’t seperate out.

So if you want your 2 ingredient peanut butter to act like a big brand peanut butter, put it in the fridge.