Tilapia is a widely available fish with a mild taste that makes it suitable for a wide variety of dishes. Tilapia fillets are generally thin, however, which presents a challenge when you grill them. If the flesh sticks to a grill’s grate, it is almost impossible to pull it free without tearing the flaky flesh apart. The keys to successfully grilling tilapia are high heat and a barrier that prevents the delicate fillets from cooking onto the the grill.
Clean and Oil the Grill
Brush the grill grate with a grill brush to remove soot and dried bits of food. Fish is less likely to stick to a clean, smooth grill grate. Brush the grill before or during the preheating stage. If there are pieces of old food stuck to the grate it is often easier to scrub them off the bars after the grill starts to heat. Scrub thoroughly: The grate should be smooth. Apply cooking oil to the brushed grate with a clean towel, folded paper towel or heat-proof basting brush. Oil acts as a barrier that helps prevent the tilapia from sticking.
Preheat the Grill Thoroughly
If the grill is sufficiently hot when you put the tilapia on the grate, the narrow bars sear the flesh, creating those coveted grill marks in the process. Seared fish does not stick to its cooking surface. Preheat the grill to medium-hot, then let it continue heating at the target temperature for an additional 10 minutes to ensure that it's primed for the tilapia fillets.
Prepare the Fish
Use the thickest pieces of tilapia you have. Thaw frozen tilapia, and pat thawed and fresh fillets dry with paper towels to remove excess moisture. Season the fillets as desired. Apply a light coat of cooking oil to both sides of the tilapia fillets. Cover them with plastic wrap, and allow them to warm to room temperature. Cold fish does not sear as effectively as room temperature fish. Tilapia fillets are relatively thin, so thawed pieces should reach room temperature in approximately 15 to 20 minutes.
Grill the tilapia until the edges of the fillets turn white and opaque. Gently slide a long, thin metal spatula between a fillet and the grill grate. Flip the fish with care to prevent it from falling apart. Do not flip the fish more than once unless necessary. It should take only three to five minutes per side to grill the tilapia. Cook the fish until its internal temperature is 145 degrees Fahrenheit according to a meat thermometer. Remove it from the grill immediately to prevent overcooking and unnecessary moisture loss, which could also lead to sticking.
Alternative Barrier: Pouches
While brushing cooking oil on the grill can prevent the fish from sticking, there are other surefire barriers that you can use. Make a pouch out of aluminum foil or parchment paper for each tilapia fillet, then grill the fish in the pouches. You can include thinly sliced vegetables in each pouch, if desired. Pouches seal moisture in, effectively steaming the fish in its own juices. Depending on how hot your grill is, you may still achieve subtle grill marks on the tilapia.
Alternative Barrier: Grilling Basket
Alternatively, you can use a grilling basket, which is a hinged, flat metal tool with long handles suitable for cooking fish and vegetables as well as other meats such as hamburgers and chicken breasts. Since the metal of a grilling basket is an open grid similar to a grill grate, tilapia should still achieve grill marks. If you grill the fillets in pouches or a basket, you do not need to oil the grate or tilapia unless you want to.