When Does Peanut Oil Go Bad?

Peanut oil is a popular frying oil because it withstands high temperatures without breaking down into smoke. Refined oils like peanut oil generally have long shelf lives, but will eventually go bad over time. 

Peanut oil lasts 1-2 years when it’s unopened and around six months once it’s been opened. You can generally use peanut oil past these dates by a bit, as long as there are no signs of spoilage.

So what are the signs that peanut oil has gone bad, and how should you store it? We have the answers!

What is the shelf life of peanut oil?

When unopened, peanut oil should last anywhere from 1-2 years. Like most oils, its shelf life shortens once you open it, since it’s then exposed to oxygen and other elements that cause it to go bad more quickly.

One of the reasons peanut oil has a long shelf life is that it’s highly refined. Refined oils have impurities removed which makes them have longer shelf lives, as well as higher smoke points – which makes peanut oil a popular oil for high-heat uses like frying.

How long does peanut oil last after opening?

Once you open a bottle of peanut oil, it should stay good for about six months before it starts to go bad. Opened peanut oil might last up to a year, but after the six-month mark, you should be watching it for signs that it’s gone bad (don’t worry, we’ll cover what those signs are in a bit!).

Peanut oil will last longer at room temperature if it’s tightly closed and stored in a cool, dark, dry place.

If you choose to put peanut oil in the fridge or freezer that’s fine, but it might not extend the shelf life drastically. Keep in mind that if you freeze peanut oil for a long time, it could negatively impact its flavor.

	Pantry	Refrigerator	Freezer
Sealed peanut oil	1-2 years	1-2 years	1-2 years
Opened peanut oil	6 months	6 months (likely slightly longer)	6 months (possibly longer)

Can you use peanut oil after its expiration date?

As long as there aren’t any signs that it’s gone bad (that’s covered in the next section), you can typically use peanut oil even after its expiration date. 

Peanut oil should stay good for a couple of months after its expiration (or use-by/best-by date). This is especially true if the peanut oil has been sealed and is past its expiration date.

If your peanut oil has been opened and is significantly past its expiration date, it’s better to replace it with a fresh bottle and not risk a potential “off” flavor ruining the flavor of your food.

How to tell if peanut oil went bad

Peanut oil is slow to go bad, but it will still happen over a long enough period, just like any type of oil or fat. Peanut oil will go bad more quickly if it’s improperly stored and frequently exposed to elements like oxygen, light, and heat.

If you spot any of the following signs, it could mean that your peanut oil has gone bad:

• It has an unpleasant odor, such as smelling rancid or chemical-like (fresh peanut oil should have a neutral or mild peanut-like scent).
  
• It has an off, sharp, bitter, or anything other than neutral or mildly peanut-like taste.
  
• The oil has changed significantly in color since you purchased it fresh.

What’s the danger in using peanut oil after it’s gone bad?

The good news is that using peanut oil that has lost its ideal freshness and quality isn’t likely to cause any serious harm. You might end up with an upset stomach or a ruined meal if the flavor of the oil was bad enough, but the likelihood that you get seriously sick from eating old peanut oil is low.

Best storage practices for peanut oil

• Store peanut oil in a tightly-sealed container in a cool, dark, dry place such as a pantry. You can refrigerate or freeze peanut oil if you want to, but there’s really no need since it stays good at room temperature for up to one year.

• Avoid storing peanut oil next to direct heat or light sources, such as next to an oven, stove, or window that gets direct sunlight. Doing so exposes the fats in the oil to degrade more quickly (go rancid), which is what makes the oil lose freshness and quality.

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