Each of McDonald’s french fries is perfectly salted and has a unique flavor unmatched by other competing chains. That flavor comes from the beef flavoring added to the fry oil.

The flavoring is used to replicate McDonald's original fry recipe, which used beef tallow for frying. It gave the fries a crunchy exterior, a pillowy interior, and a rich flavor.

However, due to health reasons, the use of beef tallow ceased in the 1990s. It was replaced with vegetable oil, and beef flavoring was later added to the recipe for tastier fries.