Fryer Oil: How Long Before You Should Toss It?

Frying oil can be reused several times, but how long it lasts depends on a few factors. The type of oil, how often it's used, and what's being fried all play a role in how long frying oil can be kept. Oil should be stored in a sealed, light-proof container in a cool, dark place. Refrigeration can also help prolong its life. Oil should be filtered after each use to remove any particles, and it's important to clean the fryer regularly. Signs that oil needs to be changed include a darker colour, a bad smell, and foaming on the surface when hot.

How to reuse frying oil

Storing and Straining the Oil

Once you've finished frying, let the oil cool completely in the frying vessel. When it's cooled, strain the oil into a clean container, such as a glass jar or its original container. A fine mesh strainer or cheesecloth can be used for this process. It's helpful to use a funnel when transferring the oil to the container.

Labelling and Storing

Label the container with the date, what the oil was used for (e.g. "chicken frying oil"), and the number of times it has been used. Store the oil in a cool, dark place until you're ready to reuse it.

Frying oil can be reused anywhere from two to eight times. There are several factors that influence this, including the type of oil, what you're frying, and how well you've strained it. There's no strict rule for when oil is no longer suitable, so pay attention to any changes in the oil. If it has become dark or dirty, is smoking before reaching frying temperature, foaming at the top, or has developed a rancid or musty smell, it's time to dispose of it.

Extending the Lifespan of Your Oil

• Use a thermometer to monitor the oil's temperature and avoid overheating it.
• Keep a fine-mesh strainer nearby to periodically clean the oil by removing any bits of batter or breading that have fallen off.
• Stick to frying battered foods or bare vegetables. Battered foods will introduce fewer impurities to the oil than breaded or floured foods.

Oil Spoilage

Oil that has gone bad will be darker than usual, smell bad, and foam on the surface when hot. If it has a soapy or chemical smell, it has likely turned rancid due to oxidation caused by age, heat, or light exposure.

Oil Types and Temperatures

Different oils have different smoke points, which is the temperature at which the oil starts to smoke. Oils with higher smoke points are more stable when cooking at high heat, so it's best to use these for frying. Good options include peanut oil, canola oil, sunflower oil, avocado oil, and vegetable oil.

Oil and Food Types

The type of food being fried also affects the lifespan of the oil. Battered and breaded foods don't come into direct contact with the oil, so the food itself doesn't make as much of a difference. However, for bare foods, fatty meats like chicken or bacon will render fat as they cook, causing the oil to break down faster.

Disposing of the Oil

Do not pour frying oil down the sink drain as it can congeal and clog your pipes. Instead, solidify it and then throw it away, transfer it to a closed container before tossing it, or recycle it if your local area offers used oil recycling.

How to dispose of frying oil

There are several ways to dispose of frying oil, some of which are safer and more environmentally friendly than others. Here are some recommended methods:

• The Container Method: Allow the oil to cool, then pour it into a disposable container with a sealable lid (such as an old food container). Seal the container and throw it into the trash.
• The Freezer Method: Pour cooled oil into an old can and place it in the freezer. Once hardened, scoop the oil into the trash. For smaller amounts, you can use a coffee mug; scoop the hardened oil into the trash, then wash the mug as usual.
• The Plastic Bag Method: Pour cooled oil into a plastic trash bag that already contains some absorbent debris, such as old paper towels or veggie peels. This helps to soak up the grease and reduce mess.
• Recycling: Some communities and businesses recycle used cooking oil, sending it to refineries to be turned into biodiesel. Check with your local recycling centre to see if they accept used cooking oil. If so, collect your oil in an empty gallon milk jug and recycle it once full. You can also contact local restaurants, as they may be equipped to handle cooking oil disposal.
• Burying: A biochemist on Reddit suggests that you can bury small amounts of oil in your backyard. The oil will be broken down by bacteria in the soil. However, this method should be approached with caution, as others warn that it could pollute water sources if not done properly.

It is important to note that you should never pour oil down the drain or toilet. Oil can clog your drains and pipes, leading to plumbing issues and costly repairs. It can also contribute to the formation of "fatbergs", masses of fat, oil, and grease that build up in pipes over time.

How to tell if fryer oil has gone bad

There are several ways to determine if fryer oil has gone bad. Firstly, oil that has been overheated or kept for too long will begin to break down and lose its hydrophobic nature, becoming less effective at preventing food from absorbing oil. This will cause food to turn greasy and lose its crispness.

Secondly, look out for physical signs of degradation. Oil that has gone bad will be darker in colour and may have a musty or fishy odour. It may also produce foam on the surface when heated and struggle to reach frying temperatures without smoking.

Additionally, rancidity is a sign of oil degradation caused by oxidation due to age, heat, or light exposure. Oil that has turned rancid will have a soapy or chemical smell.

To summarise, the key indicators of degraded fryer oil include:

• Dark colour
• Unpleasant or rancid smell (soapy or chemical odour)
• Foaming at the surface when heated
• Difficulty reaching frying temperatures without smoking

How to extend the lifespan of your oil

The lifespan of your frying oil depends on several factors, including the type of oil, the type of food being fried, and how often it is used. Here are some tips to extend the lifespan of your oil:

Choose the Right Oil

Select an oil with a high smoke point, such as canola oil, sunflower oil, peanut oil, or avocado oil. Oils with a high smoke point are more stable when cooking at high temperatures.

Maintain Temperature Control

Temperature control is crucial in prolonging the life of your oil. Avoid overheating the oil, as this can cause it to break down and become unusable. On the other hand, under-heating the oil before adding food can increase the time the food sits in the oil, leading to more particulate matter falling off and reducing the oil's lifespan.

Work Clean

Keep a fine-mesh strainer by your pot to periodically remove any bits of batter or breading that may have fallen off the food. This helps to keep the oil clean and reduces the amount of debris that can burn and affect the oil's quality.

Stick with Battered Foods or Bare Vegetables

Battered foods will introduce fewer impurities to the oil compared to breaded or flour-dredged foods. Bare foods like French fries or sweet potato fries will leave even fewer particles in the oil.

Store Properly

Allow the oil to cool completely before storing. Then, strain the oil using a cheesecloth or coffee filter set in a fine-mesh strainer to remove any remaining impurities. Store the strained oil in a tightly sealed container in a cool, dry, and dark place.

Filter and Refrigerate

Filtering the oil after each use and refrigerating it can help extend its lifespan. Keep in mind that frying oil will take on the flavour of the food cooked in it, so label the container with the date, the type of food fried, and the number of uses.

By following these tips, you can increase the lifespan of your frying oil and reduce waste and costs. However, it's important to monitor the oil for any signs of spoilage, such as a dark colour, foaming, or a rancid smell, and replace it when necessary.

Best oils for deep frying

When it comes to choosing the best oil for deep frying, there are several factors to consider, including cost, taste, quality, and smoke point. The type of food being fried and how often the oil is used will also impact the lifespan of the oil.

Canola Oil

Canola oil is one of the most common types of oil used for deep frying in restaurants due to its low prices when bought in bulk, polyunsaturated fat content, and high smoke point of 400 degrees Fahrenheit. This high smoke point allows chefs to cook their ingredients more thoroughly without the oil burning and impacting the food's quality.

Vegetable Oil

Vegetable oil is another popular option for deep frying as it has a high smoke point of 400-450 degrees Fahrenheit, which is ideal for frying foods at around 350 degrees. It is also cost-effective, as it is usually a blend of different plant-derived oils such as corn oil, soybean oil, and sunflower oil. Vegetable oil has a neutral flavour, so it won't mask the natural flavours of the food being fried.

Peanut Oil

Peanut oil is a good choice for deep frying as it has a high smoke point of 450 degrees Fahrenheit and offers a subtle nutty flavour. It is perfect for deep-frying desserts, vegetables, and meats. However, it is more expensive than other options.

Other Options

Other oils that can be used for deep frying include avocado oil, sunflower oil, safflower oil, corn oil, soybean oil, rice bran oil, and olive oil. For those who are not concerned about health, lard, beef tallow, and coconut oil are also options that can create delicious fried foods.

Frequently asked questions