Charring over open flame · The World Table

From the Lexicon, Smoke, Char & the Burnt Edge

Three points on fire's flavor dial, often confused and differently earned. SMOKE: phenolic compounds from smoldering wood dissolving onto food, sweet at low doses (fruit woods), assertive at high (hickory, mesquite), acrid when the fire is dirty (the thin-blue doctrine); it reads as flavor even cold, which is why cold-smoking exists. CHAR: localized surface carbonization (the blistered pepper, the leopard-spotted pizza cornicione, elote's blackened kernels, the steak's crust edges), bitterness deployed as PUNCTUATION against sweet and rich interiors; scraped-clean char (the burnt-on-purpose school: charred onion in pho broth, blackened citrus, burnt eggplant's smoke-from-within) is technique, not accident. THE BURNT EDGE is where char crosses into acrid, carbon without contrast. The palate law: smoke and char are BITTER-FAMILY seasonings and obey bitter's rules: they demand sweetness, fat, or acid as counterweight (barbecue sauce exists for a reason), and they compound, so a dish gets ONE fire signature loud, not three.

Read it in the Lexicon →

How to tell it is going right

The surface met the fiercest heat available (flame, a broiler, or bare hot metal) with nothing between them, and it shows as true blistering and blackening rather than gentle, even browning.
The char matches the surface’s fate: where it will be eaten, black sits in patches over deep colour with every face having had its turn, and where the skin is to be peeled away, it may go to an even black, because the char there works on the flesh below and then leaves with the skin.
It smells of smoke and toasted surface with no acrid edge that stings the nose: acrid means it went past, and acrid does not cook out.
Just under the char it is cooked (softened, steaming, collapsed, or puffed, whichever the dish wants) because the flame did the surface and the trapped heat did the rest.
A taste carries the smoke without mouthfuls of ash: the black that flakes away is a seasoning, not a layer.

Where it goes wrong It was left on one face too long or held too close, so one side carbonised to ash while the rest stayed raw, and the smell turned acrid, which follows the dish through every later step and cannot be seasoned away.

A chosen film Rick Bayless Salsa Essentials: "Chiltomate" Roasted Tomato-Habanero Salsa Rick Bayless Watch for: How far he takes the tomato and habanero skins, to blistered and blackened in patches rather than merely softened, which is the char that carries the flavor into the salsa.