You’ve probably read online that walnuts last only a few weeks at room temperature. If you don’t think that estimate is quite right, especially for unshelled walnuts, you’re in the right place.
The same places on the Internet suggest cold storage is the only way to keep store those nuts. But do you always have to refrigerate walnuts?
In my opinion, you don’t. In many situations, you can get away with leaving walnuts in the pantry or kitchen and be just fine.
Let’s talk about the shelf life of walnuts, storage options you have, and how to know if yours are spoiled.
How Long Do Walnuts Last?
Everyone, including me, agrees that going with the fridge or freezer is the best option if you want the walnuts to last as long as possible. Walnuts should keep quality for about 12 months in the refrigerator, and 24 months in the freezer (FK, UOC).
I don’t know about you, but I don’t have a ton of space in either the fridge or the freezer. And that means I’d much rather store walnuts elsewhere, preferably in the kitchen or pantry. And that’s where the discrepancies come into play.
FoodKeeper App (FK) says all walnuts last 2 to 4 weeks at room temp. That doesn’t seem to be super accurate, especially when it comes to unshelled ones. Let me explain.
Like all nuts that are available both shelled and unshelled, the latter last longer. The shell protects the kernel from elements, and this way, the nut doesn’t go rancid as easily.
In my experience, unshelled walnuts easily last months in the pantry. My family has a couple of walnut trees, so we have access to fresh walnuts each year. And after the nuts are harvested and dried, my wife and I get a big bag of those. That bag sits on top of the fridge or in a cupboard for around 6 months to a year. And almost all of the kernels turn out okay. Sure, if those nuts are already a year old, some of them will be bitter (and rancid), but most are still okay.
In short, I’d say that unshelled walnuts keep in the pantry for about 6 to 9 months. For shelled ones, that period is much shorter, possibly around two months. That’s why I prefer having in-shell walnuts that I crack as needed.
One important caveat to remember is that if you buy walnuts in bulk in a supermarket, you have no idea how old they are. Because of that, it’s impossible to say how long they will last exactly. If you buy them from bulk bins, assume they aren’t the freshest and don’t expect them to last as long. Or pick a place with high turnover, so you know what you’re getting is fresh.
Last but not least, if you’re buying walnuts prepackaged, the date on the label is quite helpful, especially for shelled walnuts. Please note that they can last a couple of months longer, especially if you refrigerate or freeze them, because that date is only an estimate.
How long are walnuts good for after expiration date, you ask? There’s no way to tell. Check the nuts for signs of spoilage (covered later in the article), and go from there. Even if the nuts are months past their date, they still might be okay to eat.
How To Store Walnuts
We already talked about cold storage and room temperature store, and you know that the fridge or freezer is best for long term storage. You also know that the pantry or kitchen is good enough for short term storage of shelled walnuts, and medium-term of unshelled walnuts. If you live in a hot climate, always refrigerate shelled walnuts.
Unshelled walnuts take a ton of space, so you probably don’t have enough fridge or freezer space to store them there anyway. I keep in-shell walnuts in a well-ventilated bag and away from any heat sources. That’s good enough for months of storage, as I already mentioned.
When it comes to shelled walnuts, you need to protect them from the outside world, i.e., air, temperature, and light. All those speed up the rancidification (WIKI) process and you don’t want that.
To take care of that, you need a resealable container or bag (just like with pecans). Sometimes walnuts come in such a bag, and if that’s the case, use it. There’s no need for repackaging or anything. The container takes care of keeping the air away, so all that’s left if to keep light and temperature at bay. To do that, place that container in a dark cabinet (short-term), or fridge or freezer (long-term).
Knowing all about storage, now’s the time to talk about what to do when you find old walnuts.
How To Tell If Walnuts Have Gone Bad?
Forst starters, check for the usual signs of spoilage, such as mold, or the kernels being dried out. If either is true, discard the nuts.
If the nutmeat looks quite alright, the next thing to do is to check if it’s rancid. To do that, proceed in the following way:
- Smell the kernel. If it smells like paint or rancid fat, it’s rancid.
- Eat one. If the taste is bitter and unpleasant, the same thing applies.
Please note that rancid walnuts often turn much darker in color, but it’s often difficult to tell based only on color. The smell and taste tests are much more reliable. Plus the kernels of black walnuts are quite dark, which doesn’t help.
If walnuts are plain bad or rancid, get rid of them. If walnuts are okay, but taste a bit stale, and perhaps not as crunchy as you would have liked, you can fix that. Here’s how.
How Do You Freshen Walnuts?
Roasting is a well-known way to get more taste out of pretty much any nuts. But before you set your oven on high and roast the hell out of your walnuts, there are a few things you should know.
First, polyunsaturated fatty acids oxidize easily when toasted for too long or at too high temperature (HL). And the more polyunsaturated fats, the more readily they oxidize. If you care about your health, you should avoid such fats.
Second, over 70 percent of fats in walnuts are polyunsaturated (ND). Some nuts, like pistachios or hazelnuts, don’t contain a lot of polyunsaturated fats, but unfortunately, walnuts do. That means that with poor toasting habits, you end up with mostly unhealthy walnuts (HL).
Fortunately, Healthline (HL) provides us with a toasting method that both gets you the results you seek (better taste and crunch) and keeps the damage done to a minimum. The whole process is super simple:
- Preheat the oven to about 284°F (140°C).
- Roast the shelled nuts in a single layer for up to 15 minutes.
- Let them cool a bit before eating.
That’s it. Nothing fancy, but you avoid most of the negative changes to the fats in walnuts and keep vitamin loss to a minimum.