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:
The type of cooking oil you use
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.
Higher temperatures break down cooking oil quickly
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.
Signs your cooking oil is past due
Needless to say there are trade offs between cost, longevity, flavor and temperature. 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.
Filtering your cooking oil extends its life
Use a filter to remove impurities: 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 your cooking oil extends its life
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.
Proper storage of cooking oil extends its life
Proper storage of cooking 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.
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.