Early one morning last month, Scott Wiener pressed his face up to a slice of pizza and inhaled. He held it aloft, checking its floppy bottom — “looking under the hood” is what he calls this well-practiced move — then daintily tore off a puffy pinch of crust.

Mr. Wiener, a Pizza Today magazine columnist and the owner of a Brooklyn-based pizza tour company, was secreted away in a back room of the Atlantic City Convention Center, judging pies in late September at the Pizza & Pasta Northeast trade show.

“White Cheddar?” he wondered aloud after a bite, while his fellow judges checked the ingredient list on a handwritten note card supplied by the contestant. He was right.

Mr. Wiener takes his duties seriously. Like the rest of the judges, he lives, breathes and believes in pizza. He was among his people: pizza people, who can toss dough acrobatically, drop technical terms like cornicione — it’s the edge of the crust — and wear shoes printed with pepperonis.