Store shelled or unshelled walnuts safely in an airtight container and store in a cool, dry place. The refrigerator is a great choice as walnuts will remain fresh for up to three months. You can also freeze walnuts for up to one year.
Usually, walnuts have a mild nutty aroma. If they smell more like used cooking oil or rancid oil, they are rancid. While rancid nuts generally aren't unsafe to eat (but definitely not healthy [HL]), their nutritional value might be diminished, plus they taste bitter. Therefore, in most cases, you want to discard them.
Consuming rancid or stale nuts like almonds, walnuts or cashews in small amounts may not immediately make you sick, but it's generally not advisable as it may hamper digestion or have other harmful effects on your body in the long term.
Walnuts go rancid when exposed to warm temperatures for long periods of time. Heat causes the fat in walnuts to change structure, which creates off odors and flavors. Fresh walnuts smell mildly nutty and taste sweet. If your walnuts smell like paint thinner, you know they're rancid.
To freshen any type of nuts before you eat (or cook with) them, toast on a baking sheet in a 350 degrees F oven for 10 minutes or place nuts in a small bowl and microwave on High for 1 to 1 1/2 minutes.
The reason why walnuts go rancid so quickly is that they contain a very high level of fatty acids, meaning that they are more susceptible to oxidation when stored incorrectly. Other nuts that go rancid very quickly include pistachios and pine nuts, which also have a very high-fat content.
Stale nuts are totally fine to eat, of course, but they do need to be processed to make them delicious again. Just toasting them in a dry pan or oven should be enough to revive them, but they'll also go in any recipe that requires nuts.
* One caveat to this: I've used Dry Canning as a secondary way of explaining vacuum sealing. It is not the oven canning method that many do - which is not a safe preservation procedure for your long-term storage. Storage Time: Up to 1 year .
Seal loose or bagged walnuts in a large GladWare® food protection container or Glad® Zipper Bag. Nuts should be placed in a dry, dark place, preferably the refrigerator.
Tip: Walnuts go rancid easily, so store raw walnuts or open jars of walnut butter in the refrigerator. Walnuts can keep fresh in the refrigerator for up to 3 months, and in the freezer for up to 1 year.
The most obvious indicator is their smell. Nuts smell sour and rancid and aren't quite pleasant. In terms of texture, stale nuts tend to feel softer and lose their trademark crunch when stale. Lastly, rancid nuts taste just like how they smell – sour and bitter.
Nuts that have gone rancid (you'll know by the acrid smell), should be tossed immediately! There's no cure for rancid nuts, but stale nuts can be revived and put to good use in baking and cooking. Refresh stale nuts by spreading them out on a parchment covered baking sheet, and baking at 350 degrees F for 10 minutes.
Pathogens on food
Indeed, nuts such as almonds, cashews, pistachios and walnuts have all been responsible for outbreaks of Salmonella poisoning.
Nuts have traditionally been considered a microbiologically safe product because of their low moisture content (low water activity). However, there have been a number of documented foodborne illness outbreaks and recalls caused by Salmonella in nuts and nut products.
Husks of fallen walnuts can become toxic to livestock, and lethal to dogs if ingested due to a mycotoxin called 'Penitrim A', which is produced by Penicillium mould.
Raw nuts can be stored in an airtight container in a cool dark place for six to 12 months. The fridge or freezer is ideal. Nuts can be refrigerated for up to four months and frozen for up to six months.
Walnuts are vacuum packaged to retain freshness, taste, and texture ensuring quality.
Smell and take a small nibble of the walnuts. Fresh walnuts will smell nutty and have a sweet, nutty taste. Walnuts that smell like paint thinner and have a very bitter taste are rancid and need to be thrown away.
How long do shelled walnuts last at room temperature? Properly stored, shelled walnuts will keep well for about 2 to 4 weeks at normal room temperature.
Microwave the nuts at one-minute intervals, stirring in between until evenly toasted and golden. Depending on the amount of nuts you're working with, this takes between three and eight minutes or so, and the results are more even and better-flavored than anything you can get out of a skillet or toaster oven.
How to choose: Walnuts that are already shelled are convenient, but be aware that they do go rancid fairly quickly. Choose nutmeats that are plump and pale; avoid any that are shriveled or discolored. For whole nuts, avoid any where the shell shows signs of mold.
After removing the husk, rinse the nuts outside with a garden hose. To check the quality of the kernel, soak the nuts in a pail of water. Good quality nuts typically sink to the bottom, whereas poor quality nuts float to the top and should be discarded.
Chestnuts are not as shelf-stable as other nuts and should be frozen. Pecans, peanuts, and walnuts are more prone to spoiling. Cashews and almonds are the least prone to spoiling. Before using nuts, always smell first to make sure they have not let oxygen in and gone rancid.