Does vegetable oil expire?
In this brief guide, we are going to answer the question “does vegetable oil expire” with an in-depth analysis of whether or not vegetable oil expires. Moreover, we are going to discuss the shelf life of vegetable oil, the proper way to store vegetable oil, and whether or not you can reuse the vegetable oil.
So without much ado, let’s dive in and figure out more about it.
Does vegetable oil expire?
Whether or not vegetable oil expires depends upon several factors including what you mean by expired vegetable oil. If you mean that the flavor and taste of vegetable oil will change after a certain time then, like all other foods, vegetable oil can expire.
Oils are generally stable microbiologically due to very low moisture content. However, they are subject to important chemical and physical changes. One of the main changes is oxidation. The primary oxidation products are (odorless and flavorless) mono-hydroperoxides that are precursors of unpleasant odors and flavors that diminish the quality of oils (1).
India is the fifth largest vegetable oil economy accounting 7.4% oilseeds, 5.8% oils and 6.1% oil meal production, and 9.3% of edible oil consumption in the world. Oilseeds are the second most important agricultural economy in India next to cereals growing at a pace of 4.1% per annum in the last three decades (2).
What we mean by expired vegetable oil is that such vegetable oil will go rancid or go stale and it won’t have the same aroma and flavor as that of fresh oil. Moreover, it will also lose its antioxidant content (1).
It is worth mentioning that you will find a “best by” or “ best before” date written on the bottle of your vegetable oil instead of the expiration date. The “best by” or “best before” date that is written on the bottle of vegetable oil refers to the quality rather than safety so vegetable oil doesn’t necessarily go bad immediately after the best before date. It is the time during which you can enjoy the peak quality and flavor of vegetable oil but you can still use vegetable oil that is past this date as long as it was stored properly (4). Together with extrinsic factors coming from the packaging and the environment, the oil’s compositional aspects primarily influence its shelf life, giving it more or less sensitivity to light, O2 , temperature, enzymes, and all the potential causes of shelf life reduction (1).
There are certain indicators that you should keep into consideration to find out whether your vegetable oil has gone rancid or not.
Vegetable oil can go rancid and it can develop that unpleasant rancid aroma that is noticeable if you take a sniff test of the vegetable oil. Moreover, if you feel some unpleasant taste or rancid taste while taking a bite of food fried in vegetable oil then it means that your oil has gone rancid and it is better to discard it.
Oxidative stability is one of the most important indicators of the quality of edible oils. Oxidative rancidity is a complex of chemical changes that imply a series of reactions between unsaturated fatty acids or acylglycerols with O2. The off-flavor compounds released make oil less acceptable or unacceptable to consumers or for industrial use as a food ingredient (1).
Moreover, the nutrient profile of the vegetable oil that has gone rancid is also degraded and it has lost most of its antioxidants. As oxidative deterioration proceeds, the level of important antioxidants such as tocopherols and polyphenols inevitably decreases (1).
You can read about different types of vegetable oils here.
How long does vegetable oil last?
Different variants of vegetable oil have different shelf lives but generally, unopened vegetable oil lasts for about 6-12 months or even more when stored in a cool, dry, and dark corner of the pantry, away from direct sunlight and heat. The shorter shelf life of vegetable oil is due to the refining process, which removes important antioxidants from the oil (1).
You can even refrigerate the vegetable oil and it does prolong the shelf life of the oil, but the increase is not much significant and truly speaking there is no need to store vegetable oil in the fridge, as it already has quite a long shelf life even when stored properly in the pantry.
It is worth mentioning that these figures are just the estimated shelf life of vegetable oil and vegetable oil can even last for more than this, provided that it was stored properly.
How to properly store vegetable oil?
- You should store your vegetable oil away from direct sunlight and heat. As sunlight and heat can increase the rate at which vegetable oil can go rancid or stale (1).
- You can store the unopened vegetable oil easily in a cool, dry, and dark corner away from direct sunlight and heat. Thus you can store vegetable oil in your pantry or kitchen cabinet (7). You can store the vegetable oil in the pantry even after it has been opened and it can last for a long time there.
- You should close the lid of the bottle containing vegetable oil as soon as you have poured the oil that you need.
Can I reuse vegetable oil after frying?
When it comes to reusing vegetable oil after you have fried something like fish, chicken, or any other thing in it, you have to keep some things in mind.
Firstly, you should let the oil cool and afterward strain the vegetable oil before storing it to get rid of the leftover particles of the previous food that you fried in it.
Moreover, there is no hard and fast rule regarding how many times you can reuse the vegetable oil, but you should try to reuse vegetable oil less than 5 times (3 times is fine), as the quality and taste of oil deteriorate with each time you fry something in it. Therefore you will notice that you won’t get the same flavor of the fried food after you have fried it for the fourth time in the same vegetable oil as you got when you fried something in it for the first time.
However, the safety of reusing oils for frying differs among different oils. Usually, tocopherols present in the vegetable oils, such as sesame oil, are sufficient to protect them against oxidation at environmental temperature. In the case of refined oils, which do not contain high amounts of antioxidants, oxidation may occur rapidly after the first or second frying procedure. Moreover, after repeated frying, all oils can oxidize, producing free fatty acids, which are harmful to health. Because of the development of harmful and reactive oxidation products when vegetable oils go rancid, they may offer health hazards such as cancer and inflammation (5,6).
Thus, the time when you start to feel a noticeable difference in the taste and smell of the food that you fried in your reused vegetable oil, you should discard the oil.
In this brief guide, we answered the question “does vegetable oil expire” with an in-depth analysis of whether or not vegetable oil expires. Moreover, we discussed the shelf life of vegetable oil, the proper way to store vegetable oil, and whether or not you can reuse the vegetable oil.
- Piergiovanni, Luciano, and Sara Limbo. Packaging and the Shelf Life of Vegetable Oils. Food packaging and shelf life. 2010, 317.
- Jat, R. S., et al. Oilseed brassica in India: Demand, supply, policy perspective and future potential. OCL, 2019, 26, 8.
- FoodKeeper. United States Department of Agriculture.
- Gravely, M. Before you toss food, wait. Check it out!. United States Department of Agriculture. 2022.
- Singh, Mukesh Kr, et al. Effects of Repeated Deep Frying on Refractive Index and Peroxide Value of Selected Vegetable Oils. Int J Res Appl Sci Biotechnol, 2022, 9, 28-31.
- Borjian Borojeni, M., A. Goli, and M. Gharachourloo. Effect of roasted sesame oil on qualitative properties of frying oil during deep-fat frying. J Agric Sci Technol, 2016, 18, 1531-1542.
- Food Storage in Home. Utah State University.