Tuna steaks require only a brief sear in a hot pan, for as little as 30 seconds up to 2 minutes per side, depending on the thickness of the cut and desired level of doneness. Fresh and frozen tuna steaks are typically sold skinned and pre-cut, making seasoning the only real prep work required. Plan on having any side dishes finished or nearly so, as the tuna steaks should have your full attention to avoid overcooking.
Types of Tuna Steaks
Bluefin tuna is prized for its silky, tender texture and pronounced meaty flavor. However, bluefin has become endangered due to overfishing and is not as readily available as other varieties.
Yellowfin and bigeye, or "ahi" tuna as they are both often referred to, are similar in quality to bluefin and more widely available. Both varieties are mild-flavored and benefit from pairing with a bolder seasoning.
Albacore is the lightest in flavor and least expensive, a great option for the sustainability- and cost-conscious.
Buying Tuna Steaks
Purchase fresh tuna steaks the day you plan to cook them for optimum freshness. Look for tuna steaks that appear moist and are firm to the touch; avoid those with a noticeably fishy smell. Tuna steaks that are around 3/4 to 1 inch thick are best for pan searing because they can stand up to high heat without overcooking.
Frozen tuna steaks can be purchased in advance since they must be fully thawed before cooking. Thaw frozen tuna in the refrigerator and use it within two days.
Pat tuna steaks dry with a paper towel to remove any excess moisture and season the steaks simply with a few dashes of salt and pepper, if you like. Tuna steaks also benefit from a brief marinade, needing only as little as 15 minutes to develop flavor, but no longer than 2 hours. Try a simple garlic and ginger soy sauce or shallot and sesame seed oil marinade. Marinades help keep the fish moist as you cook it.
Add enough olive oil to coat the bottom of a pan and bring it to a medium-high to high heat. When the oil shimmers, add the tuna steaks to the pan. Sear a 3/4-inch- to 1-inch-thick steak for 1 to 2 minutes on each side to achieve a medium-rare doneness. For rare, cook for 30 to 45 seconds per side. At temperatures above medium-rare, tuna begins to dry out.
Use a cooking thermometer inserted into the center of the tuna steak to determine doneness accurately; 125 degrees Fahrenheit indicates medium-rare, and 115 to 120 degrees F is considered rare. The United States Department of Agriculture Food Safety and Inspection Service recommends cooking fish to a minimum internal temperature of 145 for maximum food safety.