Used Fryer Oil: How Long Does It Last?

Used fryer oil can last a surprisingly long time, but it depends on several factors, including the type of oil, how it is stored, and what it is used to fry.

Oil that is more than six months old loses a lot of its virtues, and most oils should be changed after eight to ten uses. However, some people reuse their oil many more times than this. One person on Reddit claimed to know of a restaurant that had been using the same oil for almost 100 years!

To extend the life of your oil, it's important to store it correctly. This means removing it from the fryer after each use, straining it, and storing it in a cool, dark place. It's also a good idea to label the container with the date of first use and the number of subsequent uses.

Oil that has gone bad will be darker than usual, smell bad, and foam on the surface when hot. It may also have a soapy or chemical smell if it has turned rancid due to oxidation.

Used fryer oil can last up to three months if stored correctly

To maximize the lifespan of used fryer oil, it's recommended to follow these steps:

• Allow the oil to cool down completely after frying.
• Strain the oil through a cheesecloth or fine-mesh strainer to remove any food particles.
• Store the strained oil in a sealed, light-proof container.
• Keep the container in a cool, dark, and dry place, preferably in the refrigerator.
• Label the container with the date and the type of food fried.
• Use the oil within three months.

It's important to regularly check the oil for any signs of spoilage, such as a dark colour, foul odour, or foaming on the surface when hot. If the oil exhibits any of these characteristics, it should be discarded and replaced.

Additionally, to further extend the lifespan of fryer oil, it's recommended to:

• Use oils with a high smoke point, such as canola oil, sunflower oil, peanut oil, or avocado oil.
• Deep clean the fryer every three months to remove any old oil residue.
• Avoid cooking foods at temperatures above 375 degrees Fahrenheit.
• Salt foods only after deep frying.

It's best to strain and store used oil in a sealed container in a cool, dark place

It is best to strain and store used oil in a sealed container in a cool, dark place to extend its lifespan. This is because, even when stored correctly, oil can only be reused a certain number of times before it needs to be discarded. Oil that is not stored correctly will need to be replaced more frequently.

Oil should be strained to remove food residue, which can give the oil a bad taste. It should then be stored in a sealed container, such as a clean, resealable glass jar, the original container the oil came in, or a washed and dried one-litre pop bottle. The container should be labelled with the date of first use and the date of each subsequent use. It is also helpful to label the container with what the oil was used for, for example, "doughnut frying oil", as oil takes on the flavour of whatever it is used to fry.

Oil should be stored in a cool, dark place, such as a pantry or cupboard, and can even be stored in the refrigerator. Oil should not be stored in a place that is exposed to UV light, heat, or warm temperatures, as this can cause oxidation and degradation of the oil.

By storing oil correctly, it can be reused several times, however, oil should not be used past its expiration date, and even fresh oil should not be used more than six months after opening. Oil should also be discarded if it becomes dark or dirty, if it is smoking before it reaches frying temperature or foaming at the top, or if it has developed a rancid or musty smell.

Oil is no longer usable when it starts smoking, turns dark, or develops a foul odour

Oil can be reused several times, but it is important to know when it has exceeded its lifespan. The oil will let you know when it is no longer usable. It will start smoking, turn dark, or develop a foul odour. These are clear indicators that the oil has degraded and is no longer suitable for frying.

The oil may also begin foaming at the top, which is another sign that it needs to be discarded. Foaming occurs when the oil has deteriorated and formed volatile and non-volatile compounds. The volatile compounds cause the foaming, trapping air under the oil, and can lead to hydrolysis.

Additionally, if the oil has a soapy or chemical smell, it has likely turned rancid. Rancidity occurs when the oil gets oxidised due to age, prolonged exposure to heat, or light.

It is important to note that oil should not be left in the deep fryer between uses. It should be strained, stored in a sealed container, and kept in a cool, dark place until the next use.

Frying oil can be reused two to eight times, depending on the type of oil and what's being fried

Frying oil can be reused several times before it needs to be discarded. The lifespan of frying oil depends on a few factors, including the type of oil, what is being fried, and how well the oil is strained and stored.

Oil that is used for frying tends to last for up to three months after it has been opened, but this can vary depending on how often it is used, what is being fried, and the type of oil. For example, oil used for frying non-breaded meat or poultry should be changed or filtered after three to four uses, whereas oil used for frying breaded fish should be changed or filtered every two to three uses. Oils with a high smoke point, such as canola oil, sunflower oil, peanut oil, and avocado oil, are more stable when cooking foods at high heat.

It is important to note that frying oil should not be left in the fryer after use. Instead, it should be strained and stored in a lidded container in a cool, dark place. This will help to extend the lifespan of the oil. Additionally, frying oil should not be used past six months, as it can become dangerous.

To extend the lifespan of your oil, avoid cooking at temperatures above 375°F and only salt food after frying

Heat is one of the primary factors that cause oil breakdown, reducing its quality and cooking life. The higher the temperature, the faster the oil will break down. Therefore, cooking at temperatures above 375°F will cause the oil to break down more rapidly. By cooking at lower temperatures, you can help extend the lifespan of your oil.

Salt is another factor that contributes to oil breakdown. Salt increases the oxidation of fatty acids, accelerating the degradation of the oil. By salting food after frying, you can reduce the amount of salt that comes into contact with the oil, thereby slowing down the breakdown process and extending the oil's lifespan.

In addition to controlling heat and salt levels, there are several other measures you can take to prolong the life of your frying oil:

• Filter the oil frequently to remove food particles, crumbs, and impurities.
• Store oil in a cool, dark place away from direct sunlight and heat sources.
• Use a skimmer to remove any floating debris or large pieces of residue after each use.
• Cover fryers when not in use to prevent contamination.
• Educate staff or crew members on proper oil handling and maintenance procedures.
• Use a thermometer to ensure the oil does not overheat.
• Stick to battered foods, bare vegetables, or breaded foods to minimise the introduction of particulate matter.

Frequently asked questions