How Long Should You Cook Tuna On The Grill And How Can You Tell When It's Done?

The grill isn't just for steak and burgers — it can also instill a smoky sear for fish filets. Tuna steaks are a great option for grilling, with similar firmness and density to a cut of red steak. That said, tuna takes much less time to cook than your average grilled steak or chicken. So we consulted an expert about how long you should cook tuna on the grill and signs of doneness. Sheila Lucero, the culinary director at Big Red F Restaurant Group and the executive chef at Jax Fish House & Oyster Bar and Centro Mexican Kitchen, told Tasting Table that grilling tuna steaks is a fairly foolproof process thanks to tuna's coloring.

"Tuna is great because it changes color as it cooks. It is easy to visually see its doneness," Lucero said. "I love tuna rare especially if you are working with high quality tuna. You do not need to cook high quality tuna to 145 degrees [Fahrenheit]."

High-quality, fresh tuna steaks have a deep red, glossy hue, and sashimi grade tuna steaks (like this offering from OceanZen on Amazon) require little to no cooking at all. A thick tuna steak cooked to rare or even medium rare will turn a pale pink with a bit of browning on the top and bottom surfaces as they come into contact with the searing hot grill grates. A rare tuna steak will still display a dark red center between the two brownish-pink surfaces. If you use this dry rub grilled tuna recipe, expect a dark brown exterior.

Tuna steaks, like a fine cut of beef steak, require searing to get that nicely cooked crust and tender, rare interior. If you share chef Lucero's preference for rare tuna, you really only need to sear tuna for around 1 to 2 minutes per side. Again, the color change that chef Lucero describes is the visual cue you'll be looking for more than simply setting a timer. If you want a more medium doneness, you'll grill the steaks for an extra 2 minutes on each side, or until every surface of the steak's exterior has changed from red to pinkish brown. Chef Lucero also talks about cooking tuna to 145 degrees Fahrenheit, referring to the internal temperature which you can measure with this Alpha Grillers meat thermometer.

The USDA recommends cooking tuna to an internal temperature of 145 degrees Fahrenheit to kill any bacteria that might result in illness. However, 145 degrees Fahrenheit is the temperature that signifies cooking your tuna to medium. Rare or medium rare tuna should display an internal temperature of between 125 and 135 degrees Fahrenheit, thus the reason for such a short stint over a high-temperature grill. The correct grill temperature for cooking tuna steak should be a super hot 425 degrees Fahrenheit. Furthermore, the internal temperature of the tuna steak will continue to rise after you take it off the grill, so you might even consider removing sashimi-grade tuna steaks from the grill with an even lower internal temperature.