DALLAS – McDonald’s has added more locations to its test of fresh beef patties, with each of its 325 units in the Dallas area now cooking fresh beef, the Chicago Tribune reports. This expanded test only involves Quarter Pounder patties, touting those burgers as “hot off the grill.” Hamburgers and Big Macs continue to be made with frozen beef patties.

The testing process involves more than consumer feedback on the taste of the fresh patties. The chain also wants to measure the cost of using fresh beef and how cooking fresh beef impacts the kitchen’s efficiency, along with other factors.

McDonald’s prefers to test changes to beef in Texas because of how much state residents enjoy a good burger. Atlanta has become the testing ground for chicken, while the West Coast units favor salads and coffee changes are tested in the Northeast.

Tinkering with fresh instead of frozen beef is part of the QSR’s effort to increase the perception of its food freshness and quality. Other changes include eliminating preservatives and antibiotics from chicken and toasting buns.