Deep Frying: Can Oil Be Reused?

Reusing oil from a deep fryer is a common practice, especially among those wanting to save money or cut down on waste. However, it is important to be aware of the health implications of reusing oil too many times.

Reusing oil can increase your risk of cancer, as well as raising inflammation, cholesterol and acidity levels. Oil that has been used too many times will also negatively impact the taste of your food.

Reusing oil is unsafe after a certain number of uses

Each time oil is reused, it becomes more and more destabilized until it decomposes. When oil is reheated, it can raise inflammation, cholesterol and acidity levels in the body. Reheating oil can also cause it to become carcinogenic, and consuming anything that is carcinogenic has the possibility of causing cancer. The more you reheat the oil, the more aldehydes (toxic elements) are produced.

Consuming rancid oil can also increase free radicals in the body, resulting in inflammation. This rise in inflammation will eventually reduce your body's immunity and make it more vulnerable to infections and diseases.

Food fried in oil that has been reused too many times can also increase the levels of bad cholesterol in the body, increasing the risk of developing heart diseases. Reusing oil can therefore have serious, and even life-threatening, consequences for your health.

So how many times is it safe to reuse oil? Well, this depends on a few factors. The type of oil you are using, the food you are frying, how frequently you filter the oil, and the temperature the oil is heated to will all impact how many times you can reuse it. For example, for french fries and other non-breaded food items, you can reuse oil 6 to 8 times. However, for breaded, poultry, meat, and crumbly foods, you should only reuse the oil 2 to 4 times. For breaded fish, change the oil after 2 to 3 uses.

There are also some signs that the oil has gone rancid and needs to be changed. If the oil has a burnt or stale taste, is darker in colour and thicker in consistency, or is giving out more smoke than usual, it's time to change it.

The number of times oil can be reused depends on the type of oil

The number of times frying oil can be reused depends on several factors, including the type of oil, what is being fried, and how well the oil is strained and stored.

Oils with a high smoke point, such as canola, sunflower, peanut, avocado, and vegetable oils, are better suited for deep frying and can be reused multiple times. On the other hand, oils with a low smoke point will become rancid after 1 to 2 uses.

For example, when frying French fries or other non-breaded foods, the oil can be reused 6 to 8 times before it needs to be changed or filtered. For non-breaded meat or poultry, the oil should be changed or filtered after 3 to 4 uses. Breaded fish requires more frequent oil changes, approximately every 2 to 3 uses.

It is important to note that the oil should be strained and stored properly between uses to extend its lifespan. This includes allowing the oil to cool completely, straining it using a cheesecloth or fine mesh strainer, and storing it in a sealed container in a cool, dark place.

Additionally, the oil should be filtered daily in high-volume establishments where fryers are constantly in use. In these cases, the oil may need to be changed every week or two, depending on the size of the vats and the quality of the filters.

By paying attention to the type of oil, the food being fried, and proper oil maintenance, you can maximize the number of times frying oil can be reused while maintaining food quality and safety.

Oil should be strained and stored in a cool, dark place

To ensure your oil is stored correctly, you should always allow it to cool completely before pouring it into a container. It is also recommended to use a strainer or cheesecloth to remove any food particles, and to seal the container tightly. You can also extend the life of your oil by storing it in the refrigerator. However, be aware that the oil will solidify in the fridge, so you will need to let it warm up to room temperature before using it again.

By storing your oil correctly, you can help to maximise its longevity and reduce unnecessary expenses.

Oil takes on the flavour of what it's frying

Frying oil can be reused several times before it needs to be discarded. However, it's important to note that the oil will take on the flavour of whatever it was used to fry. For example, oil used for frying fish will likely leave a fishy taste, which may not be suitable for frying desserts.

When reusing frying oil, it is recommended to strain and store the oil in a lidded container in a cool, dark place. It is also helpful to label the container with the date, the food that was fried, and the number of times the oil has been used.

The number of times frying oil can be reused depends on various factors, including the type of oil, the food being fried, and how well the oil is strained. For example, oil used for frying breaded foods may only be reused 2-4 times, while oil used for non-breaded foods can be reused 6-8 times.

It is important to pay attention to the condition of the oil and dispose of it properly when it shows signs of rancidity, such as a dark colour, a rancid smell, or excessive smoking. Reusing oil for too long can have negative health effects, including increased inflammation, cholesterol, and acidity levels.

How to dispose of frying oil

Frying oil can be reused several times, but eventually, it will reach the end of its lifespan and will need to be disposed of. Here is how to do it safely:

• Do not pour frying oil down the drain. Oil can congeal and clump, clogging your pipes and leading to plumbing issues.
• Solidify it and throw it away. Use a product like FryAway to solidify the oil into a block, then throw it into the trash.
• Transfer to a closed container. Pour the oil into a sealable disposable container, such as the bottle it came in, then throw it away.
• Recycle it. Depending on where you live, you may be able to recycle used oil. Check online or with local services to see if there are any recycling drop-off points near you.
• Take it to a waste disposal site. Many cities and towns have waste drop-off sites for hazardous materials, including cooking oil.
• Give it to a restaurant. Some restaurants may accept used cooking oil, as they can sell it on.
• Mix it with absorbent materials. Add oil to sand, flour, or cat litter, which will soak up the liquid, then throw it away.
• Use it as fuel. Some people collect used cooking oil to run their vehicles on.
• Give it to a local university. For example, Loyola University Chicago processes used cooking oil into biofuel and soap.

Frequently asked questions