Why is the chicken turning gray on grill?

When your chicken meat turns grey after grilling, it’s because the internal temperature of the chicken has reached about 165 degrees Fahrenheit.

Acidic marinades

Marinating your chicken in an acidic-based marinade can also cause your meat to turn brown or grey when cooked. Marinades that contain ingredients such as vinegar, citrus juice, or yogurt are acidic.

Overcooking

If you’ve let your chicken cook for too long, the outside will become dry and overcooked while the inside will still be raw. This can cause the outside to turn grey while the inside remains pink or red.