Do walnuts go bad? (+7 health benefits)

In this article, we will answer the question “Do walnuts go bad?”, and how to tell If the walnuts have gone bad?

Do walnuts go bad?

How to tell if the walnuts have gone bad?


You can tell If the walnut is healthy or not by looking at the shell. If it looks shrunken and dried-out, the nut is bad. 

If unsure, crack open the nut to confirm your doubt.


Mold growth on walnuts is apparent in the form of nets or webs. If you notice any of this, discard the nuts immediately.

If the walnuts smell sour or rancid, they have gone bad. Fresh almonds should have a mild nutty odor. Rancid almonds are not unsafe to eat. They have a bitter taste and a poor nutritional value.

How to store walnuts?

Nuts including walnuts are a rich source of oils. The high oil content makes the nuts susceptible to spoilage due to Rancidification. Rancidity speeds up if the nuts are frequently exposed to warm temperature, temperature fluctuations, moisture, or oxygen.


Unshelled walnuts have an advantage over their shelled counterparts because the shells serve as an excellent protective covering. Due to this reason, they can be stored anywhere dark, cool, and dry. Pantry or a dark kitchen cabinet is perfect for the storage of unshelled walnuts.


  • Shelled walnuts are highly prone to spoilage and rancidity because they lack a protective shell. To make them last longer, shelled walnuts must be refrigerated or frozen.
  • An unopened package of shelled walnuts can be stored as-is in the fridge. 
  • For freezing, put the package in an air-tight container or a freezer bag.
  • Once the package is opened, walnuts must be kept in an air-tight container or freezer bag to protect them from moisture and picking up odors.

The shelf-life of walnuts

The following table shows the estimated shelf-life of shelled and unshelled walnuts under different storage conditions.

In the pantryIn the fridge 
Walnuts (unshelled)12 months 
Walnuts (shelled)Not recommended 6 months 

The shelf-life of some other types of nuts is given in the table below.

In the pantryIn the fridge In the freezer 
Past printed datePast printed date Past printed date 
Almonds 9-12 months 1 year2 years 
Brazil nuts 9 months 1 year1 year
Cashews 6-9 months 1 year2 years
Hazelnuts 4-6 months 1 year1 year
Macadamias 6-9 months 1 year2 years
Peanuts 6-9 months 1 year2 years
Pecans 6 months 1 year2 years
Pine nuts 1-2 months 1 year5-6 years
Pistachios 3 months 

Health benefits of walnuts 

Rich in anti-oxidants 

Among all the nuts, walnuts have the highest anti-oxidant content. The anti-oxidant activity of the walnuts is due to the presence of vitamin E, melatonin, and plant compounds called polyphenols.

Super plant source of omega 3s

An ounce of walnuts provides 2.5g of omega 3 fatty acids. Omega 3 fatty acids obtained from plant sources are termed alpha-linolenic acid (ALA). ALA reduces the risk of heart diseases.

Anti-inflammatory properties

One of the causes of inflammation is oxidative stress. Inflammation forms the basis of diseases like heart disease, type 2 diabetes, Alzheimer’s disease, and cancer. 

The polyphenols and their subgroup; ellagitannins, present in walnuts fight oxidative stress and reduces inflammation.

Moreover, ALA omega-3 fat, magnesium, and the amino acid arginine present in walnuts also play an important role in reducing inflammation. 

Healthy gut bacteria transform ellagitannins into compounds known as urolithins, which have excellent anti-inflammatory properties.

Promotes a healthy gut

An unhealthy gut increases the risk of obesity, heart disease, and cancer. Eating walnuts nourishes gut bacteria and stimulates the production of butyrate-producing bacteria. Butyrate is a fat that is important for the nourishment of gut bacteria.

Anti-cancerous properties

Eating walnut reduces the risk of breast, prostate, and colorectal cancers. As mentioned above, ellagitannins present in almonds are converted into urolithins which have excellent anti-inflammatory and hormone-like properties that are helpful in preventing cancers.

Aids weight loss

Walnuts keep you full for longer and help in weight loss by reducing food cravings and appetite. Eating a handful of walnuts daily can promote fat metabolism leading to weight loss.

Prevents and manages type 2 diabetes

Walnut oil has been linked with controlling blood sugar levels, hence, controlling diabetes. They may also be linked to preventing diabetes type 2 because walnuts help reduce weight.

Lower blood pressure 

Eating walnuts have been linked to reduced blood pressure levels in people with chronic hypertension and people suffering from anxiety.


In this article, we answered the question “Do walnuts go bad?”, and how to tell If the walnuts have gone bad?


Hello, I'm Sana Ameer. I'm a student of Food Science and Technology at UVAS. I like to bake and I aspire to become a Food blogger.