Grilling fish in foil is a great way to keep fish moist and infuse it with flavor. The foil creates a sealed environment that steams the fish as it cooks. This method prevents the fish from drying out on the grill. When grilling fish in foil packets, cooking time will depend on the thickness and type of fish.
Grilling Time Based on Fish Type
The time required to grill fish in foil varies based on the type of fish. More delicate fish fillets require less time than thicker, firmer cuts of fish. Here are general guidelines for grilling times for common types of fish:
| Type of Fish | Grill Time |
|---|---|
| Salmon fillet (1 inch thick) | 10-12 minutes |
| Tuna or swordfish steak (1 inch thick) | 10-12 minutes |
| Cod or halibut fillet (1 inch thick) | 8-10 minutes |
| Shrimp | 5-6 minutes |
| Scallops | 7-8 minutes |
| Tilapia fillet (1/2 inch thick) | 6-8 minutes |
Keep in mind that larger, thicker cuts of fish like tuna or salmon steaks will take longer to cook through than a thin delicate fillet. A good general rule for fillets is to grill for 8-10 minutes per inch of thickness.
Factors That Affect Grilling Time
While the type of fish is a key factor, there are several other variables that can affect how long it takes to grill fish in foil packets:
Thickness
The thicker the fish, the longer it will need to grill. Thin fillets may take 6-8 minutes, while a 2-inch thick tuna or salmon steak may need 14-18 minutes. Double the cooking time for pieces that are twice as thick.
Temperature
A hot grill cooks faster than a medium heat. Keep the temperature around 400-450°F for best results. Higher heat grills fish faster.
Bone In or Boneless
Fish with bones, like salmon steaks, take longer to cook than boneless fillets. The bones help transfer heat more slowly.
Quantity
Grilling multiple foil packets on the grill slows down the cooking time slightly compared to just one. For example, two salmon fillets may take 12-14 minutes instead of 10-12 minutes.
Additions
Packets loaded with vegetables and aromatics cook slightly slower than plain fish. The extra ingredients cause more steam production.
Flip Frequency
Flipping the packets halfway through grilling evens out the cooking. Fish that isn’t flipped may need a few extra minutes to finish cooking.
Grill Surface
The material of the grill grates also impacts cooking time. Fish will cook faster directly over the flame on open grate grills vs. those with solid metal plates.
How to Tell When Fish in Foil is Done
Visual cues can help determine when the fish is fully cooked in the foil packets:
- The flesh turns opaque and flakes easily with a fork.
- Meat thermometers inserted into the thickest part should read 145°F.
- Salmon flesh becomes a light pink shade.
- Tuna or swordfish turns white.
Start checking fish at the lower end of the estimated grilling time. You can always return it to the grill for a few more minutes if needed. Use tongs to open the foil packets carefully to avoid releasing too much steam at once.
Tips for Grilling Fish in Foil Packets
Here are some tips to get perfect grilled fish in foil packets every time:
- Cut fish into equal sized portions for even cooking.
- Brush with oil or rub with spices before wrapping in foil.
- Layer vegetables like lemon slices, tomatoes, or spinach under fish.
- Wrap packets tightly in two layers of heavy duty aluminum foil.
- Allow at least 1/2 inch between foil packets to allow steam to escape.
- Flip packets halfway through grilling.
- Insert a meat thermometer through foil to check doneness.
- Let rest 5 minutes before opening packets to finish cooking.
- Use longer grilling planks or double grill grates for more surface area.
Grilling Fish Without Foil
Fish can also be grilled directly on the grill grates without using foil. This exposes the fish directly to the heat source for faster cooking. When grilling fish without foil:
- Use a grilling basket to flip smaller pieces.
- Brush with oil to prevent sticking.
- Close lid to help retain moisture.
- Cook an average of 4-5 minutes per 1/2 inch thickness.
- Baste with glaze or sauce in the last few minutes.
Without the steam created by foil, fish may dry out quicker and require closer monitoring. Turn frequently and glaze or baste fish to help keep it moist. Smaller, delicate fillets may only need 2-3 minutes per side.
Recommended Grilling Times for Fish in Foil
As a quick reference, here are the recommended grilling times for 1-inch thick portions of popular fish when cooked in foil packets at 400°F:
| Type of Fish | Grill Time |
|---|---|
| Salmon | 10-12 minutes |
| Halibut | 8-10 minutes |
| Tuna | 10-12 minutes |
| Mahi mahi | 8-10 minutes |
| Snapper | 8-10 minutes |
| Swordfish | 10-12 minutes |
Double the cooking time for 2-inch thick portions. Reduce time slightly for thinner, smaller fillets. Use a meat thermometer to confirm fish has reached 145°F internally.
Conclusion
Grilling fish in foil is a great technique that results in tender, moist fish infused with flavor. Cooking time when using foil packets is mostly dependent on fish type and thickness. Fillet thickness directly correlates with how long the fish needs to grill. In general, figure around 8-10 minutes per inch of thickness at 400°F. Monitor for visual cues like opaque flesh and use a thermometer to ensure the fish reaches safe internal temperatures. Vary the grilling time as needed based on the size of your fish and your particular grill.