Grill
Uneven Heat: Hot Spots and Cold Corners on the Grates

What it
usually means.

Some unevenness is designed in: most grills run hotter at the back, where rising heat gathers under the lid, and cooler at the front by the knobs. Beyond that, even heat depends on every burner making the same flame and on the layer between burners and food spreading it. That layer is the heat shields, called flavorizer bars by some makers, or ceramic briquettes, lava rock or radiant plates on others. When a shield is warped, rusted through or missing, the flame beneath it strikes the grates directly and makes a hot stripe; when briquettes are soaked with fat, they flare in one spot. A burner with half its ports closed or a web in its venturi makes a short flame at one end. Wind is the outside cause: a breeze across a cart grill with the lid up strips heat from the upwind side. On infrared grills, a cracked ceramic tile or a clogged emitter screen leaves a dead patch in an otherwise glowing field. A bread test, slices laid across the grates for a minute on medium, maps the pattern clearly.