In theory, pork tenderloin is the perfect cut for grilling. It’s dressy enough to be served at an elegant dinner party, yet casual enough for weeknight supper. It’s substantial enough to be treated like red meat, yet mild enough to stand in for chicken or fish. It’s economical, healthy, readily available. Even its small size is attractive—except when you try to cook it. From my experience, pork tenderloin is just a little too small to be treated like a roast and a little too big to be treated like a steak.
Create the perfect crust
After much experimentation, I’ve concluded that grilling pork tenderloin in a covered gas grill solves the problem. (I rarely go to the trouble to light a charcoal fire for two pork tenderloins, but you can of course use this method with charcoal; see the Grilled Pork Tenderloin recipe for details) A gas grill heated to high with the lid down can effectively cook a pork tenderloin directly (like a steak) and indirectly (like a roast) simultaneously.
The key with this method is to get this sear and cook the pork tenderloin as quickly as possible, before it has a change to dry out. To develop an impressive crust (and to keep the grill from losing heat), I’ve developed the "7-6-5" method for timing the pork
The "7-6-5" Method
The "7-6-5" method for grilling pork tenderloin refers to the amount of time each side gets, with the burners on high heat: seven minutes on the first side, six minutes on the second side, and then five minutes with the grill turned off and the lid closed. The method is so reliable that I can set a timer and go about my business. I don't even have to worry about a grill flare-up: pork tenderloins are lean enough so that there's no threat of dripping fat. Here's how the timing works:
7 minutes to sear the first side, over direct, high heat. Keep the grill covered.
Next, grill 6 minutes on the second side—keeping the fire hot—so the whole tenderloin is now nicely seared.
Finally, turn off the heat, keep the lid closed, and let the tenderloin coast for 5 more minutes until it reaches an internal temperature of 145° to 150°F.