Yes, it is generally recommended to refrigerate peanut butter after opening it. Refrigeration helps to extend its shelf life and prevent the growth of bacteria and mold. However, whether or not to refrigerate peanut butter depends on the type and brand you have.

Natural peanut butter, which is made from 100% peanuts without any added preservatives, should be refrigerated. The natural oils in this type of peanut butter can separate and rise to the top, causing the product to become rancid if not refrigerated. Refrigerating natural peanut butter helps to slow down this process and maintain its freshness. Before using refrigerated natural peanut butter, it is important to stir it well to incorporate the separated oils.

On the other hand, commercial peanut butter brands, such as Jif or Skippy, often contain added preservatives and stabilizers that help prevent oil separation. These types of peanut butter can be stored at room temperature without the need for refrigeration. However, if you prefer a firmer texture or want to extend the shelf life, refrigerating commercial peanut butter is still an option.

It is worth noting that refrigerating peanut butter can cause it to become harder and less spreadable. To make it easier to use, you can take it out of the refrigerator and let it sit at room temperature for a few minutes before consumption.

It is always advisable to check the label or manufacturer's instructions for specific storage recommendations for the peanut butter you have purchased. This information can guide you on whether to refrigerate or store at room temperature.

References:

1. National Peanut Board. (n.d.). Peanut Butter FAQs. Retrieved from https://www.nationalpeanutboard.org/wellness/peanut-butter-faqs.htm

2. Still Tasty. (n.d.). Peanut Butter - Opened. Retrieved from https://www.stilltasty.com/fooditems/index/16612