Depends on which grill. If I can get the the charcoal grill running nice and hot, and the tuna steak is fully thawed, maybe 3 minutes a side. First side over direct heat, 2nd side off to the side. Let it rest for 5 minutes minimum in foil, then slice and see what you have. This one took longer because it was the propane grill since I was worried about T-storms.Craig,
How long do you hit the tuna on the grill, per side, do you look for internal temp or just color?
I guess I could be scientific about it and measure the temperature, but I was lazy. I can say that the inside rarer portion was warm to the touch, even after the rest. Wasn't sure how lightly cooked it could be and still have my Son enjoy it. He said he eats sushi all the time at the restaurant...braver than I am, especially around here (seems like lots of cooks who don't always follow food safety rules as far as food prep cleanliness, just look at the weekly food inspection reports, lol).