Maybe you used half a pack of walnuts for that fancy salad.
Perhaps you completely forgot to use the other half for a coffee cake.
And now you’re here wondering:
Oh no, are my walnuts bad? How do I tell? Have I even stored them properly?
We’ll answer all these questions today and more.
TLDR: The key thing you want to avoid with walnuts is rancidification – when fat reacts with oxygen, making the walnuts taste bad.
The best preventative measures are the walnut’s shell itself, a sealed container, darkness, and stable cold temperatures.
How To Tell If Your Walnuts Are Off

Your walnuts probably aren’t off unless you’ve forgotten about them for ages.
The chances are, your walnuts are rancid instead. Rancidity is when fats in food react with oxygen in the air, causing a foul smell and taste.
For unshelled walnuts, the shell acts as a protective layer, so your best bet is to check that. See if it has dried out and shrunk or otherwise looks weird. If it’s exhibiting any of these signs, you can crack it open to double-check, but the likelihood is that your walnuts have gone rancid.
If you have shelled walnuts, look for mold and sniff to check if it smells unusual. If your walnuts pass those tests, then feel free to give one a little nibble. It will taste bitter if it’s rancid, but it won’t be harmful unless consumed in large quantities.
How To Store Walnuts

Although shelled walnuts may be more convenient, unshelled walnuts include their protective barrier, meaning you don’t have to worry so much about your storage methods. That’s also why you shouldn’t shell walnuts before you need them.
Store unshelled walnuts in a cool, dry, dark place, away from any heat or light sources. A pantry or cool cupboard would be good options.
Shelled walnuts are more exposed to air, so they’ll go rancid faster. Therefore, you should keep them in either an unopened packet or an airtight container in the refrigerator or freezer. It’s important to make sure the packet or container is sealed, as this will stop oxygen from meeting the fats of the walnut and rancidifying them, plus it will block moisture and odors from the surroundings.
As for chopped or ground nuts, cut or grind them right before adding them to your recipe. If you have a packet of chopped or ground nuts, store them in the refrigerator as soon as you get home. Once opened, you should go for an airtight container in the refrigerator.
How Long Walnuts Last

Expect your unshelled walnuts to last a year in the pantry and about 1-2 months beyond their expiration date.
Top Tip: Portion your unshelled walnuts out in the pantry. That way, if one batch spoils, it won’t ruin your whole collection of walnuts.
Shelled walnuts usually last six months in the refrigerator and over a year in the freezer.
Walnuts: Key Takeaways
- Check for signs of rancidification if you’re worried your walnuts have gone bad. The easiest spots are a weird-looking shell, unusual smell, or bitter taste.
- Unshelled walnuts keep better than shelled walnuts, which is why they can be stored in the pantry.
- Store your shelled walnuts in the refrigerator.