The shelf life of french fries is dependent upon whether your fries are currently frozen or freshly made and how they are being stored. Once fried, the potatoes will keep in the refrigerator, or you can reheat them and even use them for new dishes before they go bad.
Many varieties of frozen french fries are available for purchase at grocery and specialty stores should you want to make them at home. No matter which brand or style of fries you choose, the amount of time they can be stored in the freezer before going bad is the same. A bag of frozen french fries will last for approximately 10 to 12 months if it is sealed. Once the bag has been removed, cook all of the contents or return any remaining fries to the freezer as soon as possible. If the potatoes begin to thaw past the point of 40 degrees Fahrenheit, do not refreeze them.
Crisp on the outside and piping hot on the inside, the ideal way to eat french fries is straight out of the fryer. Sometimes you're not able consume a full portion right away. When this happens, store any extra fries in the refrigerator so long as you can get them there within a couple hours of cooking. Wrap them in heavy aluminum foil or place them in an airtight container to ensure maximum freshness. The fries will keep this way for three to five days without spoiling.
An hour or two after cooking, even the highest quality french fries will start to get soggy. This is especially true once the fries are placed in the refrigerator and exposed to moisture. To reheat leftover fries, use a heavy-bottomed pan coated with oil to -- essentially -- fry the potatoes again. Or, bake them in a toaster oven or a regular oven under the broiler for an extra-crispy outcome. Either of these methods should make your fries taste good, before they go bad.
If you have a large portion of french fries sitting in your refrigerator -- and you don't plan to eat them -- turn them into a new dish. Chop the potatoes and add them to a frittata or an omelet as breakfast fare. Alternatively, mash the french fries and combine them with egg, flour and herbs to make a potato pancake. Or blend them into soup as a thickening agent.