Over a hot grill, steaks will cook quickly, going from very soft (very rare) to somewhat soft with a bit of a spring (medium) to quite firm (well done). Steve Johnson, chef-owner of The Blue Room in Cambridge, Massachusetts, recommends touching the steaks often and cutting into them when you think they’re done, erring on the side of undercooking since you can always cook the steaks longer, if necessary. In this video he demonstrates the procedure.