Vegetable Oil Fryer Life: How Long Does It Last?

Vegetable oil is a popular choice for deep frying, thanks to its high smoke point. This means that it can be heated to high temperatures without smoking, which is ideal for frying foods. While vegetable oil can be reused several times, it's important to follow certain guidelines to ensure food safety and maintain the quality of the oil. The oil should be strained after each use to remove any food particles, and it should be stored in an airtight container in a cool, dark place. With proper care, vegetable oil can be safely reused for up to three months after the initial use. However, it's important to monitor the oil for any signs of degradation, such as a dark or dirty appearance, foaming, or a rancid smell, as this indicates that the oil needs to be replaced.

Straining and storing vegetable oil

Firstly, it is important to let the oil cool completely in the frying vessel. Once the oil has cooled, you can begin the straining process. Ideally, use a cheesecloth set in a fine-mesh strainer, but a regular strainer will also work. If you have used the oil to fry flour-dredged foods, there may be a large layer of dirty, flour-filled oil at the bottom of the pot. Be sure to stop pouring before reaching this layer and discard it separately.

Next, pour the strained oil into a clean, dry container such as a glass jar or its original container. Using a funnel can be helpful for this step. Cover the container with a lid or seal to prevent dust or other impurities from entering the oil.

Label the container with the date, what the oil was used for (e.g. "doughnut frying oil"), and the number of times it has been used. This will help you keep track of how many times the oil has been reused.

Finally, store the container in a cool, dark place until you are ready to reuse the oil. It is recommended to store the oil in a refrigerator or freezer to extend its shelf life.

By following these steps, you can reuse your vegetable oil multiple times and reduce waste and cost. However, it is important to pay attention to the oil and detect any changes. If the oil becomes dark or dirty, smokes before reaching frying temperature, foams at the top, or develops a rancid or musty smell, it is time to dispose of it.

How to know when vegetable oil has gone bad

Vegetable oil can be reused several times before it goes bad, but it's important to know when to replace it. Here are some signs that will tell you when your vegetable oil has gone bad:

Unpleasant Odour

A rancid vegetable oil will have a subtle or strong unpleasant odour. It may smell musty or fishy.

Sharp or Bitter Taste

Bad oil tends to have a sharp or bitter taste, which can affect the quality and consistency of your cooked food.

Discolouration and Cloudiness

Vegetable oil is typically some shade of yellow, but it can vary depending on the types of vegetables used. If you notice any discolouration or cloudiness in the oil, it's probably gone bad.

Foaming

A foamy film on the surface of the oil is a sign of degradation. This can happen when the oil is still stored or after it has been used for frying.

Burning Before Reaching Smoke Point

If your oil starts to burn before reaching its original smoke point, it's a sign that it's gone bad.

Consistency Changes

Bad oil may become thicker or sticky, which can affect its performance during frying.

It's important to note that the lifespan of vegetable oil depends on various factors, such as the type of oil, the food being fried, and how well it's strained and stored. Proper storage is crucial to prolonging the life of your vegetable oil. Store it in a cool, dark, dry place, away from direct heat or light sources. Additionally, straining the oil after each use can help remove any particles and food debris, keeping it cleaner and prolonging its lifespan.

The best oils for deep frying

Deep-fried foods are golden, crispy, and delicious, but many cooks make the mistake of using the wrong cooking oil for deep-frying. The result can be off-tasting or even burnt food, a smoky kitchen, and an empty pocketbook.

The main issue is choosing an oil with an adequate smoke point. Cooking oils and fats react differently to heat, but in general, the hotter they get, the more they break down and eventually start to smoke.

That means that certain oils are better for deep-frying than others. The temperature at which a given oil will start to smoke is called its smoke point. A high smoke point means an oil can be heated to a relatively high temperature before it starts to smoke.

If you cook with oil heated past its smoke point, it will impart a burnt flavor to your food. But also, heating your oil too far beyond its smoke point could start a fire.

So, which oils are best for deep frying?

Deep frying requires higher temperatures—often over 400 degrees Fahrenheit. When choosing an oil for deep-fried delights like French fries or fried chicken, "any refined oil will work", says Eric Decker, Ph.D., professor of food science at the University of Massachusetts, Amherst. Refined oils have higher smoke points, which means they can handle the higher temperatures used in deep frying.

The refined oils that are most often used for deep frying include safflower and soybean oil, the latter of which is often labelled as vegetable oil.

Decker says the most stable picks are high in a fat called oleic acid. He recommends using peanut or canola oil.

Other good options include sunflower oil, rice bran oil, light or refined olive oil, avocado oil, and vegetable shortening.

Frying oil can be reused anywhere from two times to up to eight times — it all depends on the type of oil, what you’re frying in it, how well you’ve strained it, and more. There’s no hard and fast rule for when oil is no longer suitable for frying; instead, pay attention to your oil and detect any changes. If it’s become dark or dirty; if it’s smoking before it reaches frying temperature or foaming at the top; or if it’s taken on a different smell (besides whatever foods you’ve fried in it) that is rancid or musty, then it’s probably time to dispose of it.

How to dispose of vegetable oil

Vegetable oil can be reused several times for frying, but it's important to know when to dispose of it. Oil that has turned dark or dirty, is smoking before reaching frying temperature, foaming at the top, or has developed a rancid or musty smell should be thrown away.

Solidify It and Put It in the Trash

You can purchase a product like FryAway that will solidify the oil into a block that can be thrown away. Alternatively, you can wait for the oil to cool down and solidify on its own, and then scrape it into the trash. You can also mix it with absorbent materials like sand, flour, or cat litter, which will turn it into a solid waste that can be disposed of in the trash.

Use a Closed Container

Pour the cooled oil into a sealable, disposable container, such as the bottle it originally came in, an empty coffee can, or a glass jar. Make sure the container is tightly closed before throwing it away.

Recycle It

Check if there are any recycling centres or local businesses in your area that accept used cooking oil. Some communities and businesses recycle cooking oil and send it to refineries to be transformed into biodiesel. You can also visit the Greasecar website to find someone who wants to use the oil to fuel their car.

Other Uses

Used vegetable oil has various other uses, such as fuel for starting a campfire or charcoal grill, an eco-friendly weed killer, or bird food when mixed with oatmeal.

How to prolong the life of vegetable oil

Vegetable oil can be reused several times for frying, but there are some important steps to follow to prolong its life. Firstly, it is important to use the right type of oil. Oils with a high smoke point, such as peanut oil, canola oil, or vegetable oil, are best suited for deep frying. Oils with a low smoke point, like extra-virgin olive oil, will break down faster and may not even reach frying temperature.

To increase the lifespan of your vegetable oil, it is crucial to control the temperature. Oil breaks down when it surpasses its smoke point, so monitoring the temperature with a thermometer and adjusting the heat as needed is essential. This not only results in better-tasting food but also extends the shelf life of the oil.

Another way to prolong the life of your vegetable oil is to keep it clean. Use a fine-mesh strainer to periodically remove any crumbs, batter, or breading that may have fallen off the food. This is especially important if you are frying breaded or battered foods, as these leave behind more impurities that can burn the next time you heat the oil.

Additionally, always store your oil in a sealed container in a cool, dry, and dark place. Oil breaks down faster when exposed to humidity, light, and heat, so keeping it in a cool, dark place will help maintain its freshness.

Finally, it is important to note that frying oil takes on the flavour of the food cooked in it. So, while you can reuse the oil, be mindful of the flavours and avoid using oil for foods that may create unpleasant flavour combinations.

Frequently asked questions