Anyone who enjoys cooking a wide variety of dishes is likely to have an overflowing pantry. Bottles and jars you needed for just one or two recipes languish at the back of the cupboard.
Sesame oil is prevalent in Chinese and other Asian cuisine. In fact, its nutty flavor is characteristic of stir fries and salad dressings from across that region. It’s a great ingredient to have in your cupboard as you can evoke Far Eastern flavors with just a few drops.
If you use your sesame oil sparingly, there is a question of how long it can last. In some environments, oil can turn rancid so it’s essential that you know how to tell if your sesame oil has taken a turn for the worse. Typically, sesame oil will have a long shelf life. But you need to know how to store it, and how long it’s going to stay good.
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How Long Does Sesame Oil Last?
If you take a bottle of sesame oil and turn it over, you’ll find a use-by date that’s usually in the distant future. All oil will last for a long time if it’s stored correctly. Whether it’s sesame, peanut or good old fashioned olive oil, the bottles will usually report a use-by date of around 12 months in the future.
The truth is that these dates are rarely set in stone. Manufacturers are required by law to put a use-by date on their products and it doesn’t always correspond with the reality in the case of long-lasting products.
In the case of sesame oil, there are a few varieties you might find on the shelves. There’s toasted, untoasted and cold-pressed sesame oil (cold-pressed can be either toasted or untoasted itself). The manufacturing process has a big impact on flavor and fragrance, and toasted sesame oil can be expected to last longer than the untoasted variety.
What does have an effect on how long your sesame oil will last is if you’ve opened the bottle, as once unsealed, your sesame oil won’t last as long.
Unopened Sesame Oil
Using that use-by date as a guide, unopened sesame oil should be good for at least a year beyond that date. That means that store-bought sesame oil should be good for at least two years if it stays sealed and stored correctly.
Opened Sesame Oil
Once you open your sesame oil, it’s not going to last as long, but hey, you wanna use it, right? Exposing your sesame oil to the air will speed up any chemical reactions taking place, however slowly, to turn your sesame oil bad. You can rely on your opened sesame oil to stay good around six months beyond the use-by date.
Toasted Sesame Oil
Toasted sesame oil will last around six months longer than untoasted sesame oil. That means it should last for around eighteen months if it’s opened, and up to 2.5 years if you keep it sealed as new.
Of course, these are all rough estimates and when you’re ignoring the best-by date on a bottle you need to use your own judgement. This means it’s essential that you can assess if your sesame oil is good to use.
How To Tell If Sesame Oil Has Gone Bad
If your sesame oil gets contaminated then it’s possible that some mold could bloom inside the bottle. For this reason you’ll need to keep an eye on your oil and if you see anything unexpected inside, or a sediment forming at the bottom of the bottle, it’s time to throw it out.
However, it’s rare for oil to go moldy. More commonly, oil turns rancid. Oil has a high fat content and once your sesame oil is opened, this is exposed to the air. This kick-starts a process of oxidation in the fat which degrades your oil. If you’re keeping old sesame oil around, you need to know the signs of rancid oil.
The first indicator of rancid sesame oil is that it will darken in colour. Untoasted sesame oil will naturally be a lighter color than the toasted variety, so it’s important to note this difference before you start worrying that your oil has darkened!
A Sticky Bottle
Rancid oil develops a sticky texture, so if your sesame oil bottle is sticky to the touch that could indicate your oil has gone bad. However, any oil trapped on the outside of the bottle can go rancid whilst the oil inside is perfectly fine. A sticky bottle hints that your oil may be rancid but don’t move too hastily.
Smell And Taste
Whether your sesame oil is toasted or untoasted it should have a distinctive fragrance and taste. Familiarize yourself with how sesame oil should taste and smell. Untoasted sesame oil will be sweet and mild, whilst toasted sesame oil should pack a nutty punch.
Rancid oil will degrade such that these flavors are dramatically diminished. If an acrid smell or bitter taste develops, you’ll know your oil has gone bad.
Rancid oil is unlikely to do you any damage – the only added ingredient is oxygen, after all. But it will lose its flavor and add nothing to your dishes. To keep your cuisine up to scratch, you need to use a sesame oil that’s packed with flavor and smells great. Generally, these two tests will do – if your sesame oil still has that characteristically rich nuttiness to it, I’d say it’s good to go.
How To Store Sesame Oil
Whether your sesame oil is toasted, untoasted or cold-pressed, the advice for storing it will remain the same. As with all other oils, sesame oil will keep best if it’s stored out of direct sunlight and kept away from extreme temperature changes.
Sunlight will affect the coloring of your oil, potentially making it harder to observe if the oil is going rancid. And temperature changes will lead to the consistency of your oil changing – it might become thicker and unpleasantly gloopy.
After using your oil, ensure you replace the lid and seal it tightly. This will slow down the oxidation process that causes your oil to go rancid.
The best place for your sesame oil is inside your pantry or kitchen cupboard. In this cool, dark region it will last well for up to two years. If you use sesame on a regular basis you may prefer to keep it by your oven – as long as you keep it away from direct heat sources this won’t affect its lifespan.
Refrigerating sesame oil isn’t really necessary, but you may extend its shelf-life by a few months if you do.
Can I Freeze Sesame Oil?
Freezing oil isn’t recommended. Your sesame oil will last a couple of years outside of the freezer, and freezing it isn’t likely to extend its lifespan.
Freezing oil and bringing it back to room temperature can also compromise the consistency of your oil. When you bring a frozen oil back to room temperature it may not recombine well, and you’ll find that the liquid is inconsistent and gloopy.
Sesame oil is a delicious option for stir-frying veggies, but if you have a surplus of oil then there are many other great ways to put it to use. As a basis for a salad dressing, sesame oil brings a rich nutty flavor which pairs brilliantly with sweet flavors. And sesame oil has its uses out of the kitchen, too – sesame oil is packed with vitamin E and studies have shown that it reduces oxidative stress on the skin. If you’re worried your sesame oil is going bad, you could always have a bath in it!