McDonald's Employees Say This Is How Often Frying Oil Gets Changed

Cooking oil is one of the biggest expenses any fast food restaurant has. Data from McDonald's in London shows that its 165 restaurants dispose of 618,000 liters of oil per year. That works out to 3,745 liters, or about 989 gallons, per restaurant. USDA numbers show that about 50% of oil is absorbed into the food customers consume, while the other 50% is recycled. This means a McDonald's uses roughly 2,000 gallons per year. Those costs could get out of hand fast if oil is not kept as clean as possible and recycled responsibly. And while some restaurants may want to push the lifespan of fryer oil as long as possible, most McDonald's employees indicate the fryer oil is changed every seven to 10 days, but it depends on some factors.

Before we get into how often McDonald's changes its oil to make those legendary, best-selling french fries, it's worth knowing McDonald's does more than change it. Employees filter the oil every single day, and it happens multiple times. According to a manager who posted on Quora, after cooking six batches in a fryer, the oil is skimmed with a tool to remove any large chunks. Then the fryer drains the oil through a strainer and a filtration pad to remove any additional debris, and the newly filtered oil returns to the fryer for continued use. This helps maximize the value McDonald's gets from its oil while keeping it as clean as possible. Eventually, however, it will have degraded so much that it requires a complete replacement with new oil.

There is no set schedule for a full oil change at McDonald's because it will depend on several factors. Those include how busy the store is, the size of their fryers, and what has been cooked in the oil. A store that fries more Filet-O-Fish than another will need to change its oil more frequently, for instance. In one Reddit thread, employees in different countries report changing oil as frequently as every five days, and some not for two weeks.

In another Reddit thread, a poster mentions an EBRO machine, which is a device that measures oil quality. Once the oil reaches a certain contaminant level on the EBRO's readout, employees know to change it. Other locations may use a custom oil testing kit. It contains vials of oil and a dropper that employees use to take a sample from the fryer and compare it to the reference vials. The employee performs a simple visual comparison. If the oil is too dark, it needs to be changed.

Industry guidelines recommend that fast food restaurants change oil as frequently as every three to five days. McDonald's, because of its thorough filtration schedule, can extend the life of its oil in ways smaller chains can't. If fryer oil is not cleaned properly, not only does it become discolored and lower food quality, but it can also add an unpleasant taste as well as potential contaminants that can cause health concerns. Since any McDonald's should be keeping its oil exceptionally clean, you shouldn't have to worry about ordering some fries extra crispy next time you visit.