Can peanut butter go bad?

Yes, peanut butter can go bad over time. High fat content makes peanut butter susceptible to fat oxidation and rancidity when exposed to oxygen, light, and heat over extended periods. Unopened commercial peanut butter lasts 6 to 9 months past its printed date in the pantry, while unopened natural peanut butter lasts 3 to 6 months.

Once opened, commercial peanut butter lasts 6 to 9 months in the pantry. Natural peanut butter without added preservatives lasts about 1 to 2 months at room temperature or up to 6 months refrigerated. Signs of bad peanut butter include a sharp rancid smell, noticeable darkening, a bitter taste, or mold. If natural oil separates at the top, simple stirring restores it.