It’s fine to store olive oil in the cupboard. But nut and seed oils, including flax, sesame, and walnut oils, are best kept in the fridge and used promptly. The polyunsaturated fats in nut and seed oils can quickly turn rancid.
Not sure if it’s still good? Rancid oil has a characteristic, unpleasant odor. If an oil smells fishy or pungent, it’s best to throw it away.
Image courtesy of Shutterstock