Yes, vegetable oil does go bad – but not as quickly as you might think. So before you reach for that oil, pause but don’t panic. We’ll break things down for you.
It’s important to understand the shelf life of vegetable oil so that you don’t waste your money by allowing it to spoil – or worse, risk your health by consuming rancid oil. In fact, although it will take eating a lot of rancid oil to notice any ill effects, did you know that the consumption of too much rancid vegetable oil is linked to the development of Alzheimer’s disease, diabetes, and other scary diseases? (*)
We’ll tell you everything you need to know about the shelf life of vegetable oil so that you can make a smart shopping (and cooking!) decision.
Does Vegetable Oil Go Bad?
Let’s dive deeper into the main question.
Although vegetable oil may not develop mold or other obvious signs of spoilage, it does go bad over time.
Depending on the specific type of oil you have, you can generally expect it to last about one year after opening. This is when it is stored properly.
In fact, if you keep it in a cool, dry place and don’t open it at all, it can last for up to two years. Store your vegetable oil in a dark-colored container for the best shelf life, too, since those clear-colored containers we all love for their aesthetic value allow too much light into the oil.
However, if it’s a cheap, low-quality oil (or if it was stored indirect light or at high temperatures) it won’t last nearly as long – two to three months is about as good as you can expect.
Opening the container of vegetable oil will diminish its shelf life pretty quickly. When you open it, make sure it is sealed tightly when not in use. Although there’s nothing like that little plastic seal to keep all contaminants out, making sure the bottle is tightly closed will help slow the process of oxidation that makes vegetable oil go bad.
How Can You Tell if Vegetable Oil is Bad? 3 Tips to Tell
It can be difficult to tell if your vegetable oil has gone bad simply by looking at it.
We’ll give you a few other ways to tell the difference below.
1. Sniff Test
However, the easiest way to determine if your oil has spoiled is to give it a sniff test. If it smells or tastes sour or even unusually sharp, that’s a good sign that the oil has gone rancid.
2. Color Changes
There are a few other signs that your vegetable oil is bad too.
If the color seems to have changed or it just looks off somehow, you may want to toss it.
If you’ve been storing your vegetable oil in the refrigerator (not a recommended strategy, since it makes oil go rancid quicker), you might also notice that the oil has become cloudy and solidified a bit. This doesn’t necessarily indicate that oil has gone rancid but since it happens over time, it can get worse the older the oil is.
Don’t try to refrigerate or freeze your oil to prolong its shelf life, either. Although oil shouldn’t be stored in warm conditions, we recommend avoiding the refrigerator, too. This can accelerate the spoiling process, freezing and thawing changes the structure of the oil and actually causes it to go rancid faster. (*)
How Long Can You Use Vegetable Oil After its Expiration Date?
When determining whether your vegetable oil has gone rancid, the easiest strategy is to look for these signs of rancidity mentioned above.
However, a simpler technique that we’d like to recommend is to simply reference the expiration date. Sometimes, manufacturers list the expiration date by “sell by” or “use by” dates instead. These aren’t always the most reliable in determining whether an oil is okay to use, though, since they measure peak freshness instead of safety.
The expiration date, however, can serve as a helpful guide to tell you how long you can use the oil after its expiration date. Most of the time, it will last for three to six months after the best-by date – as long as the bottle was not opened.
If you opened the bottle, you might not be able to use the oil too far past the best by or expiration date – the liquid now has access to air and the oxidation process has started.
Is it OK to Use Expired Vegetable Oil?
The good news is that eating rancid (or expired) vegetable oil is not going to kill you. In most cases, it shouldn’t even make you sick. You’d have to consume a lot of it in order to notice any ill effects.
However, you probably won’t want to consume very much of it, since rancid oil has such a powerful, unpleasant taste and doesn’t add a whole lot to your food in the flavor department.
Avoid using expired vegetable oi when possible. Again, it won’t taste great, and there is some emerging evidence that rancid oil can accelerate the formation of free radicals in the body- something that contributes to neurodegenerative diseases, diabetes, and even cancer. (*)
Now that you know that it’s probably not a great idea to use too much-expired vegetable oil, we will tell you exactly what you should do with it instead.
How to Dispose of Expired Vegetable Oil
If you have several bottles of vegetable oil that have gone bad, you might be curious about the best ways to dispose of them.
Here are some tips:
- Don’t dump the oil straight in the trash or down the kitchen sink (it can clog kitchen pipes and local sewage systems)
- Store the oil in a sealed, disposable container – then include it in the waste bin for disposal (*)
- Freeze oil before adding to the trash if you’d rather deal with liquid oil
- When unsure contact a local household hazardous waste company for pickup
- Consider composting the oil (we recommend making sure the pile is nice and hot to avoid attracting animals and insects)
If you rarely use vegetable oil, you might not know what you should do with the oil that’s been sitting in your cupboard for such a long time.
All types of cooking oil can go bad but vegetable oil tends to last a bit longer than more delicate types, like sesame oil and corn oil (though it’s not quite as long-lived as olive oil). (*)
Store your oil the right way, and it should last for several months (if not years).
While you won’t get sick if you eat expired vegetable oil, it’s not going to taste the greatest.