A foil packet is a small, sealed pan that steams on top and fries on the bottom. The food sitting on the foil browns in fat; everything above it cooks in the steam from its own juices, which baste the whole pouch in one shared flavour. The catch is that potatoes, meat, and soft vegetables cook at very different speeds, and once the packet is sealed you can’t add things in stages. So you stage them with the knife instead: cut the slow things small and the fast things big, and they all finish at once.
The variables
- Cut size sets the cooking time. Dense vegetables (potato, carrot, sweet potato, beets) go in 1–1.5 cm (½ in) dice. Medium ones (onion, peppers, mushrooms, corn) go in 2–3 cm (1 in) pieces. Fast, watery ones (zucchini, tomato, greens) go in big chunks, or in near the top.
- Order sets the browning. Whatever touches the foil fries; whatever sits above it steams. Put the fat and the things you want crisp (potatoes, meat) on the bottom.
- Fat, salt, and a little savoury. About 1 tbsp butter or oil per packet, salt or half a bouillon cube, and pepper. The bouillon dissolves into the juices and seasons everything in the packet.
- Liquid is already in the food. Add none, or a splash at most. Vegetables and meat give off enough to steam, and more makes it soggy instead of browned.
- Size. One serving per packet, about 350–450 g (¾–1 lb) of food, in a single layer no more than 5 cm (2 in) deep. Bigger packets cook unevenly and are hard to flip.
- Heat. Medium heat: coals, not flames, or a grill or oven at about 200°C (400°F).
Steps
- Tear two sheets of heavy-duty foil about 45 cm (18 in) long and stack them. Why: one layer tears on the grate or burns through on a hot coal.
- Fat on the foil, then the slow layer. Butter or oil in the centre, the meat and dense vegetables on it in one layer.
- The fast layer on top, then the seasoning, and any butter or herbs.
- Seal it. Bring the long sides together over the food and fold them down in 1 cm folds until the seam sits just above the food, leaving some headroom. Fold each end in twice. Why: a tight seal keeps the steam in, and the headroom gives it room to circulate.
- Cook seam side up on coals or a medium grill, 20–30 minutes for vegetables and diced or thin meat, 30–40 for a raw potato base. Flip it once in the last 5–10 minutes if you want both sides browned. In a 200°C (400°F) oven, give it 25–40 minutes on a sheet pan.
- Check one. Open a corner with tongs, away from your face, and test the biggest piece of potato with a knife. Ground meat should reach 71°C (160°F); chicken 74°C (165°F). Reseal and keep going if it isn’t there. Why: packets vary with the fire, so check one before calling them all done.
- Open and serve in the foil. The juices at the bottom are the sauce.
How it fails
- Burnt bottom, raw top: flames instead of coals, a single sheet of foil, or no fat on the bottom. Rake the fire down and lift the packet to the edge.
- Hard potatoes, mushy zucchini: the cut sizes are backwards. Dice the dense things smaller, and give the soft things more size.
- Soggy and pale: too much liquid, too many watery vegetables, or a packet piled too deep.
- Leaking: a tear, or a seam that wasn’t folded enough. A leak lets the steam out and the juice into the fire. Wrap it in another sheet.
- Bland: no salt or bouillon. The steam spreads seasoning around the packet, but it can’t make any.
Variations
Camp burger pouch. The one from Camp cooking: diced potato and mixed vegetables, 115 g (¼ lb) of crumbled or pattied ground beef, half a bouillon cube, a pat of butter, and pepper.
Fish packet. A fillet on a bed of thinly sliced vegetables, with butter, lemon, and herbs. Fish cooks fast, so everything under it is sliced thin, and the packet takes 12–18 minutes.
Sausage and peppers. Sliced cooked sausage with peppers, onion, and diced potato. The sausage only needs heating, so the potato sets the time.
Prep ahead. Pack the packets at home and keep them flat in a cooler for up to a day. Leave out raw tomato and salt-sensitive vegetables until the day you cook, or they weep.