How many times can a restaurant reuse cooking oil?

The number of times  a restaurant can reuse cooking oil before it ruins the food depends on a variety of factors, including the type of oil being used, the cooking temperature, and the length of time that the oil is used. Typically frying oil can be reused 8 to 10 times. Many fast food restaurants filter their oil daily and replace it with new oil once a week. Others polish their oil in addition to filtering it for greater longevity. Larger chains develop their own custom blend of oils to capture the properties they want-flavor, longevity, temperature resistance. Some general guidelines for reusing cooking oil include:

Which cooking oils provide greater longevity?

Some oils are better suited for reuse than others. For example, neutral oils such as vegetable oil, canola oil, and soybean oil can generally be reused more times than more flavorful oils like olive oil or sesame oil. Palm oil, which is widely used, can be reused longer than any of these oils but it has been linked to deforestation and environmental damage.

How heat affects the reuse of cooking oil?

The higher the cooking temperature, the more quickly the oil will break down. As a result, it is generally best to reuse oil at lower cooking temperatures. There is a wide range of smoke points (where oils begin to break down)from 302 F for butter to 520 F for refined avocado oil.

Needless to say there are trade offs between cost, longevity, flavor and temperature.

When is cooking oil ready for the recycling bin?

As oil is used and reused, it can begin to change color and develop a rancid smell. When the oil becomes dark or has a strong, unpleasant smell, it is generally time to discard it and start with fresh oil.

What does filtering do for cooking oil?

Using a filter to remove impurities from the oil can help to extend its lifespan. Filtering the oil can help to remove any bits of food or other contaminants that may be present, which can cause the oil to break down more quickly as they are repeatedly burned and absorbed into the oil. Vito filters have been shown to increase oil life up to 50%.

“Polishing” or chemically filtering cooking oil?

 Filtering and polishing oil can extend the useable life and improve food flavor. Polishing employs a chemical to remove blood, proteins and impurities your physical filtering may not catch.

How does sunlight affect cooking oil?

 Proper storage of the oil can also help to extend its lifespan. The oil should be stored in a cool, dry place, away from direct sunlight and other sources of heat. It should also be stored in a properly sealed container to prevent contamination.If kept in the fryer overnight, the fryer cover should be on and fryer turned off.

Sunlight photo-oxidizes oils resulting in peroxides and free radicals which increases their toxicity by the formation of products such as aldehydes and ketones. Chemistry aside, this does not make for pleasant tasting food with desirable textures.

And it will definitely not encourage customers to return to the restaurant.

Simple ways to extend the life of your cooking oil

Following best practices in the kitchen can dramatically extend the life of cooking oil and therefore the number of times a restaurant can reuse cooking oil. The practices are easy but challenging to remember to do:

Utilizing best practices will extend the life of your oil. Don’t fry over 360 degrees. Oil breaks down quickly at that temperature. Don’t fill fry baskets over the oil. Crumbs and salt dropping into the fryer contaminates the oil. Burned crumbs have a very negative impact on oil and flavor

Cover the fryers and reduce the temperature of oil when the fryer is idle. Clean the fryers according to the manufacturer’s instructions.

Keep food tasting great while reusing cooking oil

There are many factors that determine how many times a restaurant can reuse cooking oil before it ruins the food. Cooking temperature, storage, filtering, polishing and what is being cooked play a role in determining the number of times a cooking oil can be used.  However, it is important to monitor the color and smell of the oil, and to discard it when it becomes too dark or has a strong, unpleasant smell. Using fresh oil can help to ensure that the food tastes good and is free from contaminants.

Tastes vary with soy and canola oils, safflower and olive oil  being popular in the U.S., peanut oil, soy and palm oil in Asia and sunflower and olive oil in Europe.