Does Cooking Oil Expire? Easy Storage Tips and Safe Reuse Ideas

Ever have one of those bottles of vegetable oil lurking at the back of the pantry? You use it to whip up a quick stir-fry and then peek at the label and ask - does cooking oil expire? Well, yes. But there's more to the story and that can help you get healthier, save money and even improve your meals.

But Does Cooking Oil Expire? Here's The Science

However, if milk spoils and bread can go moldy, can cooking oil spoil? It gets rancid through a process called oxidation because of how the cooking oil reacts with oxygen, light, and heat over time. Although rancid oil might not make you sick when you ingest just small amounts of it, the consistent consumption of rancid cooking oil is known to produce free radicals in your body.

So does cooking oil go bad is something every cook needs to consider - and the answer is yes, but it's not like other perishable items.

How Long Does Oil Last?

Different types of cooking oils and their storage practices have vastly different shelf lives. Here's a general breakdown:

• Refined Vegetable Oil / Canola Oil - 1-2 years unopened; 6-12 months opened
• Extra Virgin Olive Oil - Up to 24 months unopened; 3-6 months after opened
• Coconut Oil - 2 years (may contain saturated fats)
• Sesame Oil - 1-2 years unopened; 6 months after opening
• Flaxseed Oil - 6-8 months unopened; stored in refrigerator after opening
• Avocado Oil - 1-2 years unopened; 6 months after opening

Polyunsaturated oils (such as flaxseed and sunflower) are the fastest to go rancid and saturated oils (such as coconut oil) last the longest.

How to Decode Cooking Oil Expiry Dates

The majority of cooking oils on the market will have a "best before" or "use by" date stamped on the side of the bottle - this is the cooking oil expiry date. But it's crucial to remember that this is the date that the manufacturer estimates the oil will be at its best quality - it's not a safety date.

Even after the opening of a bottle of cooking oil, even when perfectly stored, can last for several months. However, without proper storage, the bottle can go bad long before reaching its expiry date.

It is important to always note the expiry date when purchasing the oil. Once it is purchased, the expiry date should be noted by marking it on the bottle using a marker pen.

You Must Also Read: Is Your Cooking Oil Making You Sick? Switch to Healthy Cooking Oils

How to Tell If Your Cooking Oil Is Bad

Before you use your oil to cook, try the following tests:

• Smell Test - Good oil smells oil. If it has gone off, it has a sour, musty, crayon-like or rancid nutty smell. If it smells rancid, that's because it is.
• Taste Test - Lick a bit from your finger. Rancid oil is bitter, sour or soapy.
• Visual Inspection - Check for cloudiness (in clear oils), changes in the colour or for sediments settling at the bottom. Tip: Olives oils can cloud up if you refrigerate them - that's normal and will clear at room temperature.
• Consistency - If the oil feels thicker or more gummy, it could have oxidized.

If these tests fail, don't use the expired cooking oil. Not only will the off-flavours affect the taste of your food, but the compounds formed can lead to stomach discomfort and lead to health problems over time if exposed to frequently.

Tips for Storing Cooking Oil to Extend Its Life

Storing your oil properly is the most important step towards prolonging its shelf life. Here are the best ways to store cooking oil:

1. Store Oil in a Cool Place

Keep cooking oil stored away from the stove, oven or other heat source. The pantry and cupboard are good choices. Oil oxidises very quickly when exposed to heat.

2. Keep Away from Light

Oil is highly photosensitive as well, especially when exposed to sunlight. Store it in a cabinet where it will not be exposed to light, or you can use colored or opaque packaging. This is why premium olive oils come in dark bottles.

3. Seal It Tight

The oxidation process takes place when the oil is exposed to the air. Remember to close the container each time you use it. If you have oils that you do not use daily, transfer them to a smaller container.

4. Refrigerate When Needed

Polyunsaturated fat containing oils (flaxseed oil, walnut oil, hempseed oil) should be stored in the refrigerator once opened. Chefs can keep extra virgin olive oil refrigerated for freshness; it will turn semi-solid in the cold, but that’s okay.

5. Stock Accordingly

It may be tempting to buy the largest sized bottle, but if you don't finish the oil in time, you could be spending more than just money. Buy just what you can consume in a couple of months.

Can You Reuse Cooking Oil? Safe Reuse Ideas

Recycling cooking oil is normal and safe - as long as it's done right. Here's how to do it safely:

• Strain Before Reusing - Once you have used the oil, allow it to cool and then to strain it, preferably through a fine-mesh strainer or cheesecloth. These particles speed up oil spoils.
• Inspect Oil Before Reusing - Is it rancid? Is it foamy or cloudy? If so, discard it. Don't reuse cooking oil that's past its use-by date or oil that's been over-heated.
• Minimum Reuse - Oil used to deep fry should only be reused 2-3 times. The more the oil heats, the more it breaks down.
• Use the Right Oil for the Right Food - Don't reuse an oil used for fish to fry pastry. Strong flavors transfer.
• Store Reused Oil Properly - Strain the oil and store in a tightly closed clean container in the dark or refrigerator.

How to Recycle Cooking Oil?

We know it's not good for the drain or environment to pour cooking oil down the sink. Here's what you can do:

• Composting - A little added to a compost bin is OK.
• Soap Making - Goat's milk or vegetable oils are good to use in cold-process soap.
• Lubricant - Partially used to oil squeaky doors or garden shears.
• Recycling - Keep it in the oil container and take it to a recycling centre.

Final Thoughts

So, does cooking oil expire? Yes, and it's a hard question with a variable answer depending on the oil you use, how you store it and how much you use. However, this does not mean that you will lose your money due to cooking oil. Just a few tricks on how to store cooking oil will help you save your money and get maximum benefits from it. Remember to look at the expiry date of your cooking oil, pay attention to your sense organs, and never use poor quality or decomposed oil.

FAQs

Q1. But does cooking oil really go off if it's not opened? 

Yes. The oil that forms the contents of an unopened bottle is prone to slow oxidation. Keep it away from light, store it in a cool place, and note the expiry date on the label while purchasing it.

Q2. How do I know if my cooking oil is bad? 

Take a sniff, it will emit an unpleasant odor, either sour, musty, or like a crayon. It may even have a bitter taste or appear darker than before.

Q3. Can we use cooking oil after the date? 

If it is just a little bit old and has been kept in a cool, dark environment, it may be fine. However, if it tastes and smells bad, throw it away. Consuming rancid oil will make you sick.

Q4. How do you extend the shelf life of cooking oil? 

Store oil in a closed and light-proof container away from heat. Store oils with lots of polyunsaturated fats in the refrigerator. Close tightly each time you use.

Q5. Will old cooking oil make you sick? 

It can upset your digestion and you are exposed to free radicals. Although one-time use won't make you sick, regular consumption of rancid oil can adversely affect your health.