Vegetables charred outside and hard in the middle

Each cause below lists the signs that point at it rather than at the others. Start with the signs, not with the fix.

1. The piece is thicker than the fire can cook through before the surface burns.

   common

   Signs it is this one

   • The outside is dark and the centre resists a skewer.
   • The pieces were cut noticeably thicker than the published size.

   Why it happens: A vegetable has no fat to buffer the surface and no bone to conduct heat inwards, so everything arrives through the cut face. The published cuts are chosen for that: North Dakota State specifies quarter-inch slices for sweet potato and half-inch for summer squash, and the difference is the sugar — a sweet potato scorches at a heat an ordinary potato tolerates, so the answer is to shorten the distance rather than lengthen the cook.

   What to do

   • Move the pieces to the cooler side and cover, so heat reaches the middle without adding more surface colour. — during cook, partial
   • Cut to the published thickness next time — a quarter of an inch for sweet potato, half an inch for courgette, onion and aubergine. — next time, reliable

   Next time

   • Cut to an even thickness, and match the thickness to the food rather than to the knife.

2. A dense vegetable was put on raw when it needed a head start.

   common

   Signs it is this one

   • The vegetable is a potato, a whole onion or a thick cabbage wedge.
   • It was on for the time a courgette would take.

   Why it happens: A potato has no water of its own to steam with, so heat has to conduct the whole way through dense starch. North Dakota State gives whole potatoes about forty-five minutes for that reason. Over a fire hot enough to colour anything, that is longer than the outside will survive.

   What to do

   • Finish it wrapped, or over indirect heat with the lid down, until a skewer passes through cleanly. — during cook, reliable
   • Parboil dense vegetables first, so the grill is colouring them rather than cooking them. — next time, reliable

   Next time

   • Give dense vegetables either a head start or the long published time — forty-five minutes is not a misprint.

This is BBQHQ’s diagnosis for burnt outside, underdone inside, on the foods below.

• aubergine slices
• courgette slices
• onion slices
• sweet potato slices
• cabbage wedges
• cauliflower florets
• new potatoes, halved
• whole sweet pepper
• whole onion
• halved romaine lettuce
• cauliflower steak
• butternut squash slices
• fennel wedges
• whole carrots
• broccoli florets
• whole beetroot
• whole jacket potato
• brussels sprouts
• halved plantain