Walnuts are great to keep on hand for a healthy snack, or to add to baked goods, salads, casseroles and other dishes. They're super nutritious—they add healthy fats, antioxidants and protein to your diet. Just 1/4 cup of walnuts provides 90 percent of the daily value of omega-3 fatty acids to a 2,000-calorie diet. The omega-3s and an antioxidant called ellagic acid are especially beneficial for heart and joint health.
Now that you know that walnuts deserve a permanent place in your kitchen, remember to always refrigerate them in an airtight container to keep them from going rancid. Walnuts bought in the shell and stored in a cool place can stay fresh for up to one year. Chopped and ground walnuts should be consumed within one month or kept frozen.
To determine if walnuts have gone bad, smell them. Fresh walnuts should smell mildly nutty. Bad ones smell kind of like paint thinner. Fresh shelled walnuts should feel heavy when shaken, and the kernel should not rattle. Examine the shell for tiny wormholes, which expose the walnut to air and create spoilage. If the walnuts have gone rancid, throw them away.
Walnuts can take on the odor and flavors of other foods, so store them away from foods like fish, onions or cabbage.