Vegetable oils are made up of fats extracted from seeds. Many types serve for culinary purposes such as frying, sautéing, adding flavor to dishes, creating a base for salad dressing, or helping other ingredients in recipes stick together less.
Vegetable oils are essential in the kitchen, and with different oils used for different things, you’re probably wondering just how long you can store them and what the signs of spoilage, if any, are.
How Do I Know My Vegetable Oil Has Gone Off?
Vegetable oils don’t usually become unsafe to eat but, rather, are more likely to turn rancid. Of course, if mold appears around the lid of the container or the oil smells off, throw it in the trash (not the sink as doing so clogs it up).
The signs of rancid vegetable oil are subtle. This could include:
- Discoloration–the liquid may have turned darker
- A change in smell
- It will suddenly develop a stale taste
Rancid oil is safe to eat, meaning it won’t make you sick, but in most cases, it won’t taste good, certain health benefits from different oils may disappear (as is the case with olive oil, which loses antioxidant properties), and that nice recipe you may have cooked will be ruined.
If you are unsure about the quality of your vegetable oil, test a tiny bit; if it tastes unpleasant, you know it’s time to discard it.
How Long Does Vegetable Oil Last?
The vegetable oil you have bought will come with a best-by date. If stored properly, it may last longer but this depends on the type of oil and the quality of fat. It is also dependent on what brand you have bought; if it is reputable, it will usually last longer but the downside is it’s probably more expensive.
In general, an unopened bottle will maintain freshness for the duration of the best-by date plus an additional three to six months if stored correctly.
Once opened, the oxidation process will begin to speed up, and gradually, the oil will lose its quality. It gets better: oxidation is a slow process so you don’t need to start worrying immediately! The vegetable oil will usually be fine for 6–12 months.
How To Store Vegetable Oil
Perfect storage conditions are key to prolonging the shelf life of your vegetable oil so it keeps on tasting fresh. You’ll want to prevent the oxidation process from being sped up so the ideal place is a cool, dark area, away from heat sources. Fluctuating temperatures aren’t great either as this will negatively affect the quality of your vegetable oil.
Your best bet is keeping the bottle of oil in the pantry or a kitchen cupboard that will have a constant, cool temperature. Light sources speed up the oxidation process so, again, a dark storage place is perfect.
Once opened, whatever the type of vegetable oil, always remember to ensure the lid is shut tight when not in use. Access to new air increases oxidation.
You might be wondering if it is worthwhile storing your vegetable oil in the fridge. If you live in a hot or humid area, it certainly is an option. Don’t be alarmed if it turns cloudy—some oils do this in colder temperatures. The good news is it’s still harmless to eat and it won’t affect the taste quality, especially since the cloudy color disappears once heated up during cooking.
But vegetable oil doesn’t need to be refrigerated, especially if you use it often. Remember that fluctuating temperatures will decrease the fat quality in your vegetable oil!
What’s The Bottom Line?
In short, there is a possibility that vegetable oil will go bad but due to its long shelf life, this shouldn’t be a problem that affects you.
After all, vegetable oil is commonly used in the kitchen and will probably be used up long before it has the chance to go rancid!
Just ensure the storage conditions are perfect so your bottle lasts for as long as possible.