When cooking swordfish, using a food thermometer is the most reliable way to ensure it reaches the proper internal temperature for safety and doneness. However, there are some techniques you can use to judge doneness when cooking swordfish without a thermometer.
Check for Opaqueness
One of the easiest ways to tell if swordfish is cooked through is to examine its opaqueness. When swordfish is raw, it has a translucent, shiny appearance. As it cooks, the flesh will become opaque and turn white. A thick swordfish steak should be opaque all the way through when it is fully cooked. If you see any translucent areas when you cut into the fish, it needs more time to cook.
Test with a Fork
Testing swordfish for doneness with a fork is a classic technique. When the fish is undercooked, it will feel soft and mushy when poked. As it cooks through, the flesh will become firmer. When fully cooked, the swordfish should feel solid when pressed with a fork and should flake easily. If the fish falls apart too easily, it may be overcooked.
Check for Flaking
Well-cooked swordfish will begin flaking when pressed with a fork. Check for flakes along the thickest part of the fish. If it doesn’t flake at all, it likely needs more time to cook. If the fish seems dry and flakes apart too easily, it may be overcooked.
Look for Browning
If you are cooking swordfish by grilling, broiling, baking, or pan-searing, check the exterior for browning. Once the surface takes on an opaque, cooked appearance and is nicely browned, the interior should be nearly cooked through. Swordfish is typically safe to eat when the interior reaches an internal temperature of 145°F.
Perform a Nick Test
Use a small knife to nick the thickest part of the swordfish. Check the interior color where you made the cut. When swordfish is safely cooked to 145°F, the flesh should appear white throughout with no traces of translucent or raw-looking areas.
Check Swordfish Steaks and Fillets
The thickness of the fish will determine the cooking time. Thinner swordfish steaks and fillets will cook faster than thick steaks. For fillets under 1 inch thick, the fish may need only 2-3 minutes per side to cook through. Thicker steaks from 1-2 inches may need closer to 4 minutes per side. Judge doneness by opacity, flaking, and micking tests.
Cook Until Firm for Kebabs
When cooking swordfish kebabs or skewers, cook the cubes of fish until they feel firm. Use two skewers when making kebabs to prevent spinning. Swordfish holds up well for kebabs since it is a meaty, firm fish.
Check Larger Fillets and Steaks
For very large swordfish fillets or steaks over 2 inches thick, it can be tricky judging the doneness, especially the center near the bone. You can make a small cut into the center after searing or grill marking the fish to peek and see if it is opaque in the middle. Large pieces may need 10 minutes or more per inch of thickness.
Use a Meat Thermometer For Accuracy
While the techniques above can help estimate when swordfish is cooked through, using an instant read meat thermometer offers the most precision. To ensure any harmful bacteria are killed and the fish is thoroughly cooked, swordfish should reach an internal temperature of at least 145°F.
For the most accurate reading, insert the thermometer into the thickest part of the fish, taking care not to touch any bones. Different doneness levels correspond to various temperatures:
| Doneness Level | Internal Temperature |
|---|---|
| Rare | 125°F |
| Medium-Rare | 130°F |
| Medium | 140°F |
| Well-Done | 145°F |
Check Swordfish Roasts and Larger Cuts
When cooking large cuts of swordfish like roasts or whole fillets, use a meat thermometer to accurately gauge doneness, especially if cooking beyond medium doneness. The outer portions of the fish may appear done while the interior is still undercooked. Test temperature in a few spots to ensure even doneness.
Conclusion
Swordfish is cooked to perfection when it reaches an internal temperature of 145°F. Checking for opacity, flaking, and firmness can help determine approximate doneness. But using an instant read thermometer provides the most reliable results to ensure the fish is fully cooked for safety and quality. With these simple methods, you can enjoy perfectly cooked swordfish even without an oven thermometer.