It takes eight to 20 minutes to cook a 1-inch thick steak medium rare on a grill. The 12-minute time variation occurs due to the setting and temperature differences within commercial grills.
A 1-inch thick steak is generally grilled for four to five minutes over direct medium-high heat, then moved to a part of the grill that receives indirect heat for an additional four to 10 minutes.
To determine the exact amount of time to grill a 1-inch thick steak on a particular grill, the steak is first grilled for the recommended time over the direct heat. Then, it is checked for desired doneness after every two-minute time block that the steak is set over indirect heat. It is important to let the steak rest for three minutes before cutting into it to ensure that the juices of the steak are properly redistributed throughout the meat.