how long to cook porterhouse steak on gas grill
1 Turn steaks over on opposite side in 5 minutes. 2  Put lid back down. 3  Let it cook for another 3-4 minutes to reach medium rare, or 5-6 minutes to reach medium. 4  To tell the temperature, you can use a simple hand test to determine the doneness of your grilled porterhouse steaks.f you love steak, a porterhouse is a special treat, especially if it's grilled to perfection. Here's Elias Iglesias, executive chef of Morton's, The Steakhouse, to show how to cook a porterhouse steak on a gas grill.