Do Walnuts Go Bad? – Full Analysis

Do Walnuts Go Bad? – Full Analysis

Do walnuts go bad? Yes, walnuts can go bad. As with a lot of nuts like this one, they do not go “bad” exactly but more like they turn rancid. This is because of the oil that is inside these types of nuts. When this happens, it gives them a taste that is bitter and makes them inedible.

Storing them correctly can give them a longer shelf life. The shelf life also depends on whether they are shelled or unshelled also.

How to Tell if Walnuts are Bad

When trying to decide if the walnuts have gone bad, the way you tell depends on whether it is shelled or unshelled.

The best way to tell if the walnut is bad is to look at the shell. If it has gone bad, the shell will look shriveled and shrunk. In other words, a rancid walnut will have an unhealthy shell. If the shell looks okay, crack a few open to see what is inside.

You may also see a layer with dark spots on meat inside, which is a sign of mold growing over them. They also smell unpleasant with the oil giving you an odor of cooking oil. Because of the oil that has turned rancid, they will taste bitter. Although they are not unsafe to eat, it is still best to throw them away.

Sometimes the walnut will look okay so you will then need to try one to see if they taste bitter or if they are still good to eat. They can look okay and you won’t notice they are bad until you taste one.

You can also shake them to see if the kernels or meat inside rattle. They should also feel heavy when fresh. Always look the shell over very carefully to see if there are any tiny wormholes that expose it to the air.

How Long Do Walnuts Last? Shelf Life [Chart]

Type of Walnut Pantry Refrigerator Freezer
Shelled 2-4 weeks but best stored in refrigerator 9-12 months Up to 24 months
Unshelled 12 months and about 1-2 months past the “best-by” date N/A 12 months

Why Do Walnuts Go Bad or Rancid?

Walnuts can go bad, or rancid, if the oil in walnuts is exposed to prolonged warm temperatures, oxygen, moisture, or temperature changes. It occurs when the fat in the walut reacts with oxygen.

To keep this from happening you need to make sure that you are storing them correctly. 

How to Store Walnuts

Because they can turn rancid if not stored properly, the best way to store Walnuts is to buy unshelled ones and put them in the refrigerator or even freeze them. For short term use, they can be stored in the pantry.

You should keep the shelled walnuts in an airtight container in the refrigerator or freezer. For the unshelled ones, they need to be stored in a cold, dark place away from the sunlight.

When storing them in the refrigerator, you can toss the package in there as long as it has not been opened. If you decide you want to freeze them, make sure that they are in a resealable zip lock freezer bag or an airtight container.

After they are opened and shelled tight, they need to go into some tight zip-lock bag or airtight container to keep the moisture out. It will also help to keep out strong odors.

Shelled walnuts will pick up strong odors so this is why they need to be in an airtight container. Some of the strong odor food to keep them away from are onions, fish, or cabbage.

To ensure the best taste, it is recommended to store the shelled walnuts whole and not chopped or ground up. This should be done right before you are ready to add the walnuts to the recipe.

What are Walnuts?

Walnuts are a type of tree nut with a tough hard shell. Inside the shell, the nut meat looks sort of like a tin brain. It has a rich, sweet taste and is one of the most widely-consumed nuts in the world.

Two of the more common varieties are the California black walnut and the English walnut but there are over 50 varieties. The world has enjoyed eating them for over 8,000 years with the majority coming from China and California

What Types of Food Contain Walnuts?

Because of their delicious flavor and crunchiness. walnuts are used in a variety of foods.

Walnuts, along with pecans, are great foods to use in desserts. The next time you check out a dessert counter, look at all the different foods that contain walnuts. They are usually in cakes, tarts, and cupcakes, and also used as a decoration.

Additionally, walnuts don’t burn easily so they are ideal for foods that go in the oven.

What are the Nutritional Benefits of Walnuts?

One of the best things about walnuts is that they are rich in omega-3 fatty acids. This type of fat helps support a healthy immune system, healthy hair, and is good for the heart.

But walnuts also contain antioxidants which are important for preventing cancer. For people who are trying to maintain their weight, walnuts have a good mix of fats and protein, so they don’t have to rely on junk food to get in their calories.

Walnuts have folic acid which is vital for a woman who is pregnant because it helps prevent birth defects.

If you ever have a moment, check out all of the nutritional benefits of walnuts and try to fit this healthy nut into your diet.

Health Benefits of Walnuts

  • Helps to reduce the risk of heart attacks, cardiovascular disease, and stroke
  • Decreases the harmful cholesterol level and triglycerides.
  • Rich in antioxidants that can help fight the oxidative damage in your body.
  • A good source of omega-3 fat
  • May help to decrease inflammation
  • Walnuts are rich in health-promoting bacteria that promotes a healthy gut and could help reduce the risk of disease.
  • Walnuts have polyphenols that could help to reduce the risk of certain cancers, including prostate and breast cancer.
  • They may help you control hunger and your appetite
  • Can help manage your Type 2 diabetes and lower your risk of developing it.
  • May help lower your blood pressure
  • Support good brain function

How to Use Walnuts in Your Diet 

  • Sprinkle on fruit salads or on leafy greens
  • Grind them up finely and put them in sauces and dips
  • Chop them and use them in whole-grain breads
  • Crushed them to use as a coating on chicken
  • Put them on top of yogurt or oatmeal
  • Chop and put them in pita or wrap sandwiches
  • After lightly browning, add them to stir-fry recipes


  • Most walnuts will go bad after the best-by-date on the package unless they are stored correctly.
  • The unshelled walnuts will last longer because the shell is a great protective barrier
  • Walnuts have folic acid, antioxidants, and omega-3 fatty acids.
  • Shelled walnuts will last a few months past the best-by-date but the longer you store them, the more will be bad or rancid after cracking them open.
  • If you buy a pack of ground or chopped nuts, they need to be stored in the refrigerator and should be placed there as soon as you get home.
  • When storing your unshelled walnuts in the pantry portion them out so if one batch goes bad, it won’t affect all of them.