Why doesn’t peanut butter go bad?

In this article, we will explore the question, “Why doesn’t peanut butter go bad?” We will also delve into other significant topics, including shelf life and proper storage methods for peanut butter.

Why doesn’t peanut butter go bad?

The explanation can be found within its components. Peanuts possess natural oils that turn rancid upon exposure to oxygen (1, 2 and 3). To counteract this, manufacturers employ hydrogenated oil to envelop the peanuts, shielding them from oxygen and preserving their freshness.

Moreover, the hydrogenation process elevates the melting point of peanut butter, enabling it to remain stable at room temperature without segregating into its original oil and peanut constituents (4). 

Consequently, it is improbable for your peanut butter to spoil unless it is left out for an extended duration or if you introduce additional bacteria into the container (1 and 5).

It’s crucial to remember that natural homemade peanut butter lacks stable ingredients to slow down oxidation and lacks additives to preserve freshness in room temperature conditions.

How long does peanut butter last?

 Peanut butter has a commercial expiry date of 6 to 9 months if unopened, and two to three months if opened (6). 

When stored in the refrigerator, unopened peanut butter remains stable for up to 12 months, and once opened, it can be consumed for 3-4 months in refrigeration (6).

Peanut butter is a spread made from ground, dry-roasted peanuts. It can be commercially produced with added hydrogenated fat or stabilizers, or it can be natural without any additional fats or stabilizers (6). 

Peanut butter lasts quite long due to its composition, the high-fat content and the low moisture levels. Stabilizers like hydrogenated vegetable oils or palm oil provide structural integrity to the nut butter. It keeps the oil from separating (7).

 Additional ingredients are often used to modify its texture. Preservatives like sodium benzoate are added in small amounts to inhibit microbial growth (1 and 5).

Generally, natural peanut butter may not contain stabilizers or preservatives; therefore, it requires refrigeration for a longer shelf life. This is also why one often sees a layer of oil floating over a jar of natural chunky peanut butter. 

Natural peanut butter may also contain peanut chunks that can shorten its shelf life; therefore, it needs to be stored with care (6).

Can peanut butter go bad? 

Peanut butter can go bad. In fact, peanuts are one of the most common allergens in the world. However, the reason peanut butter is actually safe to consume is because of the way it’s made: peanuts are crushed into a paste with low moisture content, making it very difficult for bacteria to grow (2 and 5).

If you want to further reduce your risk of food poisoning, there are some tips you can follow (1 and 5):

Make sure your jar has an airtight seal.

Don’t leave it open for longer than necessary.

Avoid dipping your fingers or anything else into the jar more than once.

How do you know if peanut butter is bad?

Peanut butter is typically sold in commercial packaging with an expiration date. There are several signs that indicate peanut butter has gone bad. These include:

  1. Rancid or off odor, which is noticeably different from the fresh smell. Spoiled peanut butter may have a soapy or bitter smell.
  2. The texture and appearance of spoiled peanut butter also change, becoming hard and dry compared to the soft and creamy texture of fresh peanut butter. 
  3. The color of spoiled peanut butter may appear lighter than its usual brown color. 

Additionally, the taste of peanut butter turns sour when it goes bad due to the rancidity of fats. Normally, peanut butter has a nutty and rich taste, so if it tastes sour or bitter, it should not be consumed (3).

How should you store peanut butter?

Peanut butter has a long shelf life when stored properly, despite the high fat content and presence of stabilizers and preservatives. To prevent spoilage, it is important to follow proper storage conditions (1). 

These include storing peanut butter in a cool, dark, and dry place, although refrigeration can further extend its shelf life (6). 

Peanut butter is typically packaged in jars or airtight containers to minimize environmental contamination and air exposure (3).

 Closing the lid tightly after each use and using safe packaging can help prevent rancidity caused by air oxidation (1).

Can you freeze peanut butter to keep it from going bad?

Yes, you can freeze peanut butter without affecting its taste or texture. However, freezing may not be the most optimal option for extending the shelf life of your peanut butter. Alternatively, storing peanut butter in the refrigerator can keep it stable for up to 12 months (6).

What are the possible risks of eating spoiled peanut butter? 

The risks are associated with health issues. Consuming rancid peanut butter could cause digestive issues (2 and 5). The presence of microorganisms can lead to food poisoning or other infections (1). Keeping peanut butter in the freezer for a long time could potentially result in its expiration, leading to a decrease in nutritional value (2).


In this article, we have addressed the question, ‘Why doesn’t peanut butter go bad?’ Many manufacturers use hydrogenated oil to coat the peanuts, protecting them from oxygen and maintaining their freshness. When stored correctly at 77ºF or 25°C, unopened peanut butter can last 6 to 9 months, while opened peanut butter can last up to two months.


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2. Huang, T. ; International Association for Food Protection , Des Moines , USA , Food Protection Trends. Consumer storage period and temperature for peanut butter and their effects on survival of Available from: https://<ixmlns=”http://www.w3.org/1999/xhtml”>Salmonella</i> and <i xmlns=”http://www.w3.org/1999/xhtml”>

3. Isleib TG, Pattee HE, Sanders TH, Hendrix KW, Dean LO. Compositional and sensory comparisons between normal- and high-oleic peanuts. J Agric Food Chem. 2006;54(5):1759–63. Available from: https://doi.org/10.1021/jf052353t

4. Inyang UE, Oduma OV. Fatty Acid Profile and Oil Stability of Butter Made from Peanut Paste Supplemented with Sesame Seed Paste. Asian Food Science Journal. 2020 Aug 12;16(4):1-9.


5. Linscott AJ. Food-Borne Illnesses. Clin Microbiol Newsl [Internet]. 2011;33(6):41–5. Available from: http://dx.doi.org/10.1016/j.clinmicnews.2011.02.004

6. USDA. Food Safety and Inspection Service [Internet]. [cited 2023 May 29]. Available from:


7. Suchoszek-Łukaniuk K, Jaromin A, Korycińska M, Kozubek A. Chapter 103 – Health Benefits of Peanut (Arachis hypogaea L.) Seeds and Peanut Oil Consumption. In: Preedy VR, Watson RR, Patel VBBT-N and S in H and DP, editors. San Diego: Academic Press; 2011. p. 873–80. Available from: https://www.sciencedirect.com/science/article/pii/B9780123756886101033.