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Can Vegetable Oil Go Bad?

Can vegetable oil go bad? If you use it rarely, you might not know what you should do with oil that has been stored in your cupboard for a long time and whether it can be used, or not.

If you’re a cook, you probably use vegetable oils pretty often and you know how to deal with them. This article will provide you with all the information you need.

Pecan avocado salad and condiments
(credit: fran hogan)

How long does vegetable oil last?

There are quite a few kinds of vegetable oils, like soybean oil, sunflower oil or peanut oil. Their shelf life, however, is quite similar to one another. As long as your vegetable oil is unopened and stored properly, it should be fine for at least two years, probably for a lot longer. Once you’ll open the bottle, the oil in it should be fine for at least a year.

If you’ll store vegetable oil the right way, you’ll prevent it from going bad for a longer period of time, even much longer.

There is, however, another thing worth mentioning – the taste of oil changes after some time and in many cases you won’t be pleased with those changes, especially if you plan to use the oil in a salad. It becomes rancid.

Few plastic bottles of vegetable oil
Image used under Creative Commons from

A few words about storing vegetable oils. First and foremost, you should remember that vegetable oil should be stored in a cool and dry area. Storing it in the pantry is quite popular and it’s a good choice.

Storing vegetable oil in the refrigerator, however, isn’t such a great idea. Keeping the bottle out of light is also a good thing, so putting it in a cupboard in the pantry seems to be the best thing you can do.

One more thing – once you’ll open the bottle, make sure it’s sealed tightly when you’re not using the oil. That will prevent any contaminants and air from getting into the bottle. If oil has constant access to fresh air, the process of oxidation starts and it makes the oil deteriorate faster.

Does vegetable oil expire? How to tell if vegetable oil is bad or rancid?

As a matter of fact, vegetable oil expires. Even when it’s stored properly, it will happen, eventually. However, in many cases going bad isn’t a problem because vegetable oil usually goes bad after quite some time.

As I’ve mentioned above, the taste of oil changes with time, so after a few years the oil won’t be of good quality and, even though it won’t be spoiled, you’ll probably decide to discard it, because it’s rancid.

In some cases, that are very rare though, vegetable oil can go bad. How to tell if it’s bad? You’ll easily notice it, just examine its looks, smell and taste. If you’ll notice that its color is changed (it’s dark now), it has developed an off odor or it tastes wrong, discard it. If it tastes stale, it’s probably rancid and it won’t help you in cooking anymore.

Olive oil and tomatoes

As you can see, the answer to the main question “can vegetable oil go bad?” is affirmative. However, in most cases going bad isn’t a problem because vegetable oil will be fine for a lot longer than its “Best by” date says, provided it’s stored properly.

The biggest problem is that oil deteriorates and after some time its taste changes and it becomes rancid. Because of that, after a couple of months after the “Use by” date you’ll probably decide to throw it out.