Have you ever noticed that when you open a new jar of peanut butter, there is an oil that floats on top of the peanut butter?
Well, no need for concern as it is a natural phenomenon.

Authentic peanut butter releases its oil and appears on the surface- so if you notice some oil on top, it's a sign of your peanut butter being natural.
Peanut fats tend to be liquid at room temperature. The melting point of peanut oil is well below room temperature and is around 3°C (=37°F).

The melting temperature of fats relies on the number of unsaturated fats it contains- If it has more unsaturated fatty acids, the lower the melting point. In peanut oil, research finds that over 80% of the fatty acids are unsaturated.

Grinding

When peanut butter is made, the nourishing fats in peanuts are released. Ground peanut butter essentially consists of peanut particles floating in their oils.

Why does it split?

Although you need a lot of fat, and even if the liquid fat helps to generate silky peanut butter, there is a drawback to using so much liquid fat. The amount of fat is so high that the particles can float in it because the particles aren't packed closely together.

As a result, over time, a process known as sedimentation will cause the peanut particles to settle down the oil, which explains why some peanut butter has a liquid coating on top. Peanut oil makes up this layer!

Why doesn’t all peanut butter have oil on top?

Big peanut butter manufacturers use hydrogenated oils that convert unsaturated and healthy fats into saturated fats. This process can increase shelf life -and the outcome is peanut butter that stays solid, but the downside is detrimental.
Saturated fats can cause problems like cholesterol and increase your chances of heart issues.

How can you stop the splitting without hydrogenized oil?

As natural peanut butter is produced without hydrogenated oils, it melts at room temperature- the fix is simple-just store your natural peanut butter in the refrigerator -and it'll be good to go!

However, since peanut oil has a melting point of 3C, wouldn't it remain liquid in a refrigerator?
That is partly accurate. This type of oil doesn't have a single temperature at which all of its molecules turn from solid to liquid (as is the case for water).
Instead, this only happens inside a temperature range. Therefore, some fats in the refrigerator are still liquid while others have hardened at slightly above 3C (27F). However, that is sufficient to prevent the peanut butter particles from slipping through the oil.

So next time you get shocked at the sight of oil on top of your peanut butter, don’t be alarmed- Simply stir the peanut butter and spread, or store it in the refrigerator to avoid the oil layer entirely!