Any adventurous eater who has wandered into the woods of modern Nordic cuisine has probably tripped over a loaf of rye bread. There is wonderfully chewy rugbrod at Great Northern Food Hall in Grand Central Terminal, spice-scented Swedish limpa at Plaj in San Francisco, and darkly rugged toast at Bachelor Farmer in Minneapolis.

But none of it is the rye bread that most Americans know. Unlike a smooth, ivory-crumbed, faintly tangy loaf — the bread that clasps the ideal pastrami sandwich together — rye breads from Scandinavia and other parts of Northern Europe are bumpy, nutty and fragrant. They can be as dark as chocolate cake and as spicy as gingerbread. They are often powerfully sour and even more powerfully delicious.

Riding a wave of interest in ancient grains, rye is sprouting in many influential kitchens — in pasta, porridge, brownies and, most gratifyingly, in bread.

“Rugbrod is like wine in France or olive oil in Italy,” said Claus Meyer, the owner of Great Northern Food Hall and several new Nordic food enterprises in New York. He is also a founder of Noma in Copenhagen, a chef and a bread evangelist. “It is more than food,” he said. “It is history. It is culture, and agriculture.”