Ingredients

• Peanut butter does not contain much water because it is mainly made up of oils.arachidi image by lacuraludovico from Fotolia.com
  
  Most peanut butters contain up to 16 g of fat in 2 tbsp. Not only is peanut butter made up of natural peanut oils, other vegetable oils are often added. Peanut butter has a moisture content of about 2 percent because it does not contain much water, mainly oil. Without water, fungi and bacteria are unable to grow.
  
  

Fat Breakdown

• Peanut butter is susceptible to rancidification. Oxygen will break down the fats in the peanut butter, changing the flavor and odor. The more peanut butter is exposed to oxygen, the more likely it is to become rancid.
  
  

Misconceptions

• Just because peanut butter becomes rancid doesn't mean that it will hurt your body. Rancid peanut butter will only taste and smell bad. Sometimes individuals do not even notice that they are eating rancid peanut butter because everyone's taste buds are different.
  
  

Types

• All-natural peanut butters do not include extra oils. These natural peanut butters have a higher moisture content and need to be refrigerated after opening to prevent bacteria and fungi growth.
  
  

Appearance

• If your peanut butter appears to have water on top and the expiration or "use by" date has not yet passed, it is caused by oil separation. This problem can be resolved by stirring the peanut butter.