Keep acid off bare aluminum

Use heat-rated parchment suitable for the cooking temperature as an inner layer with sturdy foil outside, or a suitable covered grill pan. Lemon juice and salty liquid should not sit directly against bare aluminum. Leave a little room for steam while sealing the seams tightly. Paper-lined packets belong away from direct flames. Open the seam away from your face because a rush of hot steam can escape immediately.

Fold the foil with space above the fish for steam and keep the seam facing upward. Avoid openings underneath that let the juices escape. Open a parcel away from your face when checking the fish. Keep hot liquid away from hands and remove the foil before serving the portion. Keep raw ingredients refrigerated; clean hands, utensils and surfaces after contact, and use fresh plates for cooked food.

The parcels do not have to finish simultaneously. Start unusually thick portions first and identify them with a different fold so they are easy to find when checking. Insert the thermometer through the opened seam; a new hole in the bottom would leak vegetable juices. For further cooking, refold the seam tightly and keep the packet in the same indirect zone.

The recipe

Serves 4

Ingredients

  • 4 cod portions, about 6 oz / 160 g each
  • 1 small zucchini
  • 2 carrots
  • 1 scallion
  • 2 tbsp olive oil
  • ½ tsp fine salt
  • ½ tsp black pepper
  • 4 tbsp water
  • 1 tbsp lemon juice
  • 2 tbsp chopped parsley

Method

  1. Cut carrots and zucchini into very thin strips and slice the scallion finely. Divide vegetables among four prepared parcels, place fish on top and add oil, salt, pepper and one tablespoon water to each.
  2. Preheat an outdoor grill for medium heat, with a direct cooking area and a separate unheated zone. Clean the grate before adding food. Keep the cooler side clear so pieces can finish gently or move away from any flare-up.
  3. Seal tightly and cook indirectly with the lid closed for about 15–20 minutes. Keep away from open flames and glowing coals. Carefully open one packet to measure the thickest fish center.
  4. Check the thickest part with a clean food thermometer: fish should reach 145°F / 63°C. Timing varies with thickness and the grill, so use the suggested minutes to plan rather than as a doneness guarantee.
  5. Reseal and cook longer if necessary. Add lemon juice and parsley only to the finished fish. Open on plates and serve the vegetable juices as well, checking carefully for any remaining bones.

Storage

Refrigerate leftovers promptly in shallow containers, within two hours or within one hour above 90°F / 32°C. Keep at 40°F / 4°C or colder and use within three to four days. Reheat only the portion needed to 165°F / 74°C throughout; discard food left out beyond those limits.

Use grilling equipment only in its intended location and follow the manufacturer’s instructions. Timing is not a substitute for checking doneness.