Cooking Oil In A Deep Fryer: How Long Does It Last?

Deep frying requires a lot of oil, so it's tempting to reuse it. Restaurants and fast-food chains often do this, filtering the oil daily and changing it weekly or bi-weekly. However, reheated oil can increase cholesterol, acidity, and inflammation levels and cause gastrointestinal issues, so it's important to know when to change the oil in your deep fryer.

How to store cooking oil in a deep fryer

Cooking oil can be stored in a deep fryer, but it is not recommended to do so for extended periods. Oil can degrade and become rancid, leading to potential health issues such as increased cholesterol, acidity, and inflammation levels. It is best to change the oil frequently, depending on usage and maintenance.

If you plan to store cooking oil in your deep fryer, ensure that it is thoroughly heated before each use. This helps to prevent any excess batter or impurities from settling and prolongs the oil's lifespan. Keep the fryer covered with a cloth when not in use to avoid exposure to air and potential contaminants.

When storing oil in the deep fryer, it is crucial to maintain hygiene and prevent contamination. Always strain or filter the oil after each use to remove any food particles or debris. Breaded items, for example, tend to leave behind crumbs and flour particles that can burn and infuse the oil with a bitter flavour.

To store the oil, allow it to cool completely, then seal it in a clean, dry container with a tight lid. Glass jars or the original oil bottles are suitable options. Store the sealed container in a cool, dark, and dry place, away from heat sources like the stove, oven, or microwave.

By following these steps, you can safely store cooking oil in your deep fryer for a short period. However, for optimal freshness and to maintain the quality of your fried foods, it is recommended to change the oil frequently and practice proper oil maintenance.

How to know if cooking oil has gone bad

Cooking oils can go rancid over time, typically after 1-2 years, depending on storage conditions. Opened oil will go rancid faster than unopened oil because it has more exposure to air and oxygen.

• Check the expiration date.
• Give it a sniff test. If it smells sharp, metallic, bitter, or rancid, it has gone bad.
• Check if it has an off-putting taste.
• Observe its colour. If it has a darker, more unnatural colour, it may have gone bad.
• Check its texture. If it has a slimy and thick texture, it has likely gone bad.
• Observe the smoke point. If the smoke point has dropped, the oil has likely gone bad.

Some other factors that can cause oil to go rancid faster are:

• Leaving the container open.
• Leaving the oil in direct sunlight.
• Exposing the oil to high temperatures.
• Not filtering the oil after frying.
• Storing the oil near the stove.

How often to change cooking oil in a deep fryer

The frequency with which you should change the cooking oil in a deep fryer depends on several factors. These include the type of oil, the food being fried, the frequency of filtering, the number of uses, and the temperature at which the oil is heated.

For example, if you frequently fry breaded foods, such as poultry, meat, or crumbly foods, the oil should be changed after 2 to 4 uses. This is because food crumbs require a high temperature to fry, which can cause the oil to go rancid more quickly. On the other hand, for non-breaded foods like French fries and other vegetables, the oil can be reused for 6 to 8 uses.

It is important to note that reusing oil for too long can have negative health consequences. Reheated cooking oil can increase inflammation, cholesterol, and acidity levels in the body, leading to an increased risk of heart disease, stroke, and chest pain. Therefore, it is recommended to regularly monitor the condition of the oil and change it when it shows signs of deterioration, such as a colour change, unpleasant odour, or excessive foaming or smoking during cooking.

To extend the lifespan of the oil, it is advisable to use a fine mesh or oil filtration system during cooking. Additionally, storing the oil in a tight-lid container in a dark and cool place can help maintain its quality.

In a commercial setting, the frequency of oil changes can vary depending on the volume of food being cooked and the type of food. Some restaurants change their oil daily, especially in high-volume fine dining establishments, while others may change it weekly or every few days.

How to dispose of old cooking oil

Cooking oil can go rancid and cause various health issues, so it's important to change the oil in your deep fryer regularly. The frequency of changing the oil depends on factors such as the type of oil, the food being fried, the frequency of filtering, the number of previous uses, and the temperature at which it is heated. For example, oil used for frying breaded foods should be changed after 2-4 uses, while oil used for non-breaded foods can be reused 6-8 times.

When disposing of old cooking oil, it is crucial to remember that it should never be poured down the drain. Here are some methods to dispose of old cooking oil responsibly:

• Cool and store: Allow the oil to cool down completely. You can place the pan in the freezer to speed up the process. Once cooled, store the oil in a sealed container such as a jar or bottle. Make sure to label the container clearly.
• Dispose of with regular trash: After the oil has solidified, you can scrape it into the trash bin. You can also mix the cooled oil with absorbent materials such as paper towels, oats, or rice and then throw it away. However, check with your local waste management guidelines or your municipality's hazardous waste disposal center, as some places may have specific instructions for oil disposal.
• Composting: Small amounts of oil can be soaked up with paper towels and placed in a compost bin. However, do not add large amounts of oil or grease to your compost bin, as these can cause issues with decomposition.
• Recycle: Some cities and companies are now accepting donations of used cooking oil for the creation of biodiesel. Check with your local recycling center or waste management facilities to see if they have similar programs.
• Reuse: Cooking oil can often be reused multiple times if properly filtered and stored. Strain the oil through a fine-mesh sieve or coffee filter to remove any food particles, and then store it in a clean, sealed container away from direct heat and light. However, it is important to monitor the quality of the oil and dispose of it properly once it starts to degrade.

Health risks of using rancid cooking oil

Rancid oil is a health hazard and should not be consumed. Rancid oil has an unpleasant smell and taste, and can cause digestive system distress. It can also deplete vitamins B and E from your body.

Rancid oil forms dangerous free radicals, which can cause long-term cell damage and increase the risk of chronic diseases such as Alzheimer's, diabetes, heart disease, and cancer. Free radicals have also been shown to damage arteries and function as carcinogens.

Consuming rancid oil can also increase inflammation, cholesterol, and acidity levels in the body, which can lead to heart disease, stroke, and chest pain. It can also cause unpleasant symptoms such as bloating, acidity, and stomachaches.

To prevent the health risks associated with rancid oil, it is important to change the oil in a deep fryer frequently, depending on the type of oil, the food being fried, and the frequency of use. Storing oil in a cool, dark place, such as a pantry or cupboard, can also help extend its shelf life.

Frequently asked questions