Grilling: direct and indirect heat

Why

Direct heat above the coals or burner radiates so strongly onto the surface that it quickly forms a crust, but the heat reaches the centre of a thick piece far more slowly; indirect heat beside them works like an oven under a closed lid and cooks the piece through without burning the surface. That is why thin slices, vegetables and skewers are grilled directly, while thick steaks, bone-in chicken or a whole fish are seared directly and finished indirectly. When fat drips onto the heat, flames and smoke form, carrying polycyclic aromatic hydrocarbons (PAHs) that settle on the meat, and long cooking at high temperature produces heterocyclic amines (HCAs) in the meat. The risk of both is shown mainly in animal studies with very high doses and studies in humans are inconclusive, but the US National Cancer Institute and the German BfR give similar advice: don't char, don't let fat drip onto the heat and keep flames off the meat; the NCI also advises cutting away burnt parts. Sugar in a marinade or glaze browns faster than the meat, which is why it is brushed on only towards the end.

How to do it

• Spread the coals over only half of the grate, or light the burners on one side of a gas grill only; the other side is for finishing.
• Light charcoal in a chimney starter or with solid firelighters; never pour lighter fluid onto hot or warm coals and never use petrol or methylated spirits.
• Grill only outdoors, never in the home, a garage or a tent: hot coals give off carbon monoxide, which you can neither see nor smell; bin the ashes only after 48 hours.
• If flames flare up, move the meat to the cooler side; grill fatty pieces in a tray, ideally stainless steel, that catches the dripping fat.
• Finish thick pieces indirectly under the lid and check doneness with a probe thermometer; brush on sweet glazes only in the last few minutes.
• Turn the meat often and cut away blackened, burnt parts.

If it goes wrong

Burnt outside and raw inside: cut off the blackened surface and finish the piece on the indirect side under the lid until the core reaches a safe temperature. Don't tear meat that has stuck – wait a moment until the crust releases from the grate by itself; next time heat the grate well, clean it and wipe it with oiled paper held in tongs.