Do Nuts Ever Expire?

Certain foods have quite the ambiguous shelf life. Unlike fresh fruits such as bananas that can go from unripe to overripe overnight, other food items like oil, flour, and rice seem to be able to last a lifetime. Though if you have ever smelt or accidentally tasted a rancid almond or two, you know that nuts fall in the former category.

Nuts contain polyunsaturated fatty acids which is what makes them so great for brain and heart health. However, polyunsaturated fats also spoil quicker than any other fats. Live Science explains that the structure of a food item as well as its taste and smell changes when it is exposed to oxygen. This process of oxidation is essentially what makes nuts go bad and causes them to expire. The site says that polyunsaturated fats, in particular, are very sensitive to oxygen and that once nuts have started oxidizing, they can go bad pretty quickly.

There are ways to bend the rules of nut expiry dates, though. According to Eat By Date, if you read the label on a bag of nuts carefully, most have a best by date instead of an expiration date. This means that, while there is a recommended date that you should ideally use your nuts by, they are not necessarily going to go bad the day after. In fact, if you store them well, nuts can be used well past their best by date.

How quickly a bag of nuts will go bad varies among different types of nuts and how you store them. Pine nuts can be safe to consume for about one to two months past their best by date when stored in the pantry and five to six months in the freezer. Almonds, on the other hand, can be good for another year at room temperature and for two in the freezer (via Eat By Date). So, how exactly can you make your nuts stay fresh for longer?

The golden rule to extending the shelf life of nuts, The Spruce Eats says, is to store them in airtight bags or containers to maintain a steady level of moisture. Eat By Date recommends portioning a big bag of nuts into several smaller bags for storage because after a bag is opened, nuts will start oxidizing quickly. Once bagged, nuts will be fine to use for about three months at room temperature, six months in the refrigerator, and about a year or more in the freezer. The exact time varies depending on which nut you are storing but this is a good rule of thumb to follow.

The best way to tell if your nuts are starting to go bad is by giving them a good whiff. If you notice that they smell stale, you can pop them in the oven for 10 minutes at 350 degrees F. However, if the nuts have already started smelling rancid, there's no saving them.