Quick Answer: Lay slices of plain white bread across the entire grate on medium heat, close the lid for 60 to 90 seconds, then look at the browning pattern - dark slices mark hot spots, pale slices mark cool zones. Almost every grill has a hot centre or a hot back, and gas grills usually run hotter above the burner tubes and cooler at the edges. Once you know the map, you place food by zone rather than by guesswork, and the lid thermometer becomes a rough guide rather than a source of confusion.

You cook six identical pieces of chicken and get three doneness levels. The grill is not broken.

It is just not one temperature, and it never was.

Why is the grate never one temperature?

The lid thermometer measures air temperature near the top of the dome, which is not the surface temperature of the grate and can be off by a large margin in either direction.

On a gas grill, heat rises directly from burner tubes, so the grate is hottest in a stripe above each tube and cooler in the gaps and at the edges where heat escapes.

On a charcoal grill, the distribution follows the coal bed exactly, which is rarely as even as it looks. A slightly deeper section of coals can be a hundred degrees hotter than a thin one.

Edges always lose heat to the surroundings, and the perimeter of any grill runs cooler than the centre - which is why a burger in the corner takes twice as long.

Wind creates asymmetry from outside. A breeze from one side cools that side and can drive extra oxygen into a charcoal fire on the other, and this shifts as the wind does.

And the back is often hotter on grills with a rear-hinged lid, because heat pools where the dome is deepest and escapes at the front where the lid meets the body.

The bread test, step by step

Preheat as you normally would, with the lid down, to a medium setting. The map is only useful if you make it at a temperature you actually cook at.

Cover the entire grate with slices of plain white bread, edge to edge, leaving no gaps. Cheap sliced white is ideal because it browns fast and evenly.

Close the lid for 60 to 90 seconds. Any longer and everything is uniformly black, which tells you nothing.

Lift the lid and photograph the whole grate from directly above. The photo is the point - you will not remember the pattern accurately in a fortnight.

Read it as a heat map. Dark brown is your searing zone, golden is your general cooking zone, pale is your resting and indirect zone.

Repeat on high if you sear a lot, because the pattern can shift at different burner settings.

Then repeat the whole exercise once a year, or after you clean or replace burners, because burner ports clog unevenly over time and the map changes with them.

How to actually use the map

Sear on the dark zone, finish on the pale zone. This is the two-zone method that most grilling advice recommends, and knowing your own map is what makes it precise rather than approximate.

Put thick cuts on the moderate zone and thin ones on the hot zone. A thick chicken breast on a searing hot spot burns outside before the centre is safe; a thin one needs that heat to get colour before overcooking.

Use the coolest zone as a holding area for food that is done while something else finishes. This is what makes cooking for a group manageable.

Rotate rather than flip repeatedly. Moving food to a different zone and turning it 90 degrees does more for even cooking than flipping it back and forth in the same place.

Place vegetables and delicate items around the perimeter deliberately, rather than fitting them wherever there is space.

And stop trusting the lid gauge for anything except trends. An instant-read thermometer at the food is the number that matters; the dome gauge only tells you whether the grill is roughly where it was ten minutes ago.

A cheap infrared surface thermometer makes the map quantitative if you want actual numbers, and it takes about two minutes to sweep the grate.

5 Mistakes That Make Uneven Cooking Worse

Mistake 1: Trusting the lid thermometer as grate temperature. It measures dome air temperature, often at a completely different value from the surface your food is on.

Mistake 2: Filling the grate edge to edge. A completely covered grate blocks airflow and exaggerates the existing hot and cool zones rather than evening them out.

Mistake 3: Opening the lid constantly. Every lift drops the temperature substantially and cools the perimeter faster than the centre, which makes the unevenness worse each time.

Mistake 4: Never cleaning the burner ports. Clogged ports produce genuinely uneven flame, and a grill that cooked evenly two years ago may have developed a cold corner you have unconsciously worked around.

Mistake 5: Ignoring wind direction. Setting up so the wind hits one side creates an asymmetry no map accounts for. Turning the grill 90 degrees is free and often solves it.

The one people rarely consider is the fourth. Uneven cooking that developed gradually gets attributed to technique, when the actual cause is a burner that needs ten minutes with a wire brush.

FAQ: Grill Hot Spots, Answered

How do I find my grill’s hot spots?

Cover the preheated grate with plain white bread slices, close the lid for 60 to 90 seconds, then photograph the browning pattern from above. Dark is your sear zone, pale is your indirect zone.

Why is my lid thermometer so inaccurate?

It measures air temperature at the top of the dome, not the surface of the grate. The two can differ by a large margin, and the gauge is only useful for tracking trends.

Where are hot spots usually located?

On gas grills, in stripes directly above the burner tubes, with cooler edges. On charcoal, wherever the coal bed is deepest. The back is often hotter on rear-hinged lids, and the perimeter is always cooler.

How often should I remap?

Once a year, and after cleaning or replacing burners. Burner ports clog unevenly over time, which changes the pattern gradually enough that you may not notice.

Does wind really matter?

Yes. It cools one side and can feed extra oxygen to a charcoal fire on the other. Turning the grill 90 degrees to the wind is free and often fixes an asymmetry no map accounts for.

TL;DR:

• Cover the grate with white bread, close the lid 60 to 90 seconds, and photograph the browning pattern - that is your heat map.
• The lid thermometer reads dome air temperature, not grate surface temperature, and is only useful for trends.
• Gas grills run hot above burner tubes and cool at the edges; charcoal follows the depth of the coal bed.
• Sear on the dark zone, finish on the pale zone, and use the coolest area to hold finished food.
• Remap yearly and after cleaning burners, and turn the grill 90 degrees to a strong wind.

Ten minutes and a loaf of cheap bread fixes a problem most people blame on technique for years.