Do you love rye bread? Maybe you do — or maybe you just think you do.

“The Jewish deli rye most New Yorkers are used to is actually made with at least 50% wheat flour, not so much rye,” the founder of Amy’s Bread, Amy Scherber, said. “That’s why it’s so fluffy and tall, instead of compact and dense like rye bread should be. The flavor of that bread actually comes primarily from caraway, not from rye.”

It may sound scandalous, but it’s true: The bread that generations of New Yorkers have thought of as classic rye isn’t actually very rye-y at all, and would be laughed out of the bakeries of Europe, where rye bread originated and is still popular. Deli rye has its uses, but it’s practically Wonder Bread when compared to a true rye, which features a hearty crust and a big, bold flavor all its own.

“In Germany, there are laws on the books about this,” the director of the King Arthur Flour Bakery in Norwich, Vt., and author of “Bread: A Baker’s Book of Techniques and Recipes,” Jeffrey Hamelman, said. “Over there you can’t call something rye bread unless it has a minimum of 90% rye flour, which is almost unheard of in the United States. It creates a very robust flavor, with a pleasing acidity, a mild tang.”

“A true rye has a denser crumb, so a 1-pound loaf will look kind of small and compact compared to a 1-pound loaf of fluffy white bread,” Ms. Scherber added. “It also has a very nice fragrance. Wheat smells a bit sweeter, while rye smells a bit sharper, almost spicy.”The bread’s density makes it ideal for toasting and as a platform for hors d’oeuvres, and its strong flavor goes well with cured foods like smoked meats and fish. If you think lox tastes good on a bagel, try it on a slice of real rye.

Ms. Scherber sells several kinds of rye at her three Manhattan shops (672 Ninth Ave., 212-977-2670; 250 Bleecker St., 212-675-7802, and in the Chelsea Market, 75 Ninth Ave., 212-462-4338), including a French rye bread made from almost 100% rye flour. The long, fairly narrow loaf looks like a slightly thicker stick of French bread, at least until you cut into it.The interior is very dark, like whole wheat bread (the more rye flour in the dough, the darker the bread will be), and the center is extremely dense but moist. The flavor is strong and the aroma is intensely earthy, almost funky, like raw molasses. It couldn’t be farther removed from a caraway-studded deli rye — although Ms. Scherber makes an excellent version of that as well.

Because rye grows well in poor soil, rye bread has a long history with Eastern European peasant cultures.You can see that heritage in Brooklyn’s Greenpoint neighborhood, where many Polish bakeries feature rye bread. One of the best is the Old Poland Bakery (190 Nassau Ave., Brooklyn, 718-349-7775), which sells three kinds of rye bread, including a super-dense 100% rye sweetened with a bit of honey.

But one lament comes up again and again when talking to bakers about rye bread: They love making true rye but have found only minimal customer acceptance. Abe Faber, co-owner of Clear Flour Bread in Brookline, Mass., has been on a bit of a crusade to change that — first locally, and then, he hopes, nationally.

“You can’t just take people who are used to eating white bread and then suddenly expect them to have a frame of reference for a traditional rye,” Mr. Faber said.”So when we roll out a bread that we think is cool, I try to talk it up, encourage people to try it, even give it away.You have to do that for maybe a year or two before people will accept it.”

And his persistence is paying off. “We’re definitely selling more of it, and then you get a snowball effect,” he said. “If you have only six rye loaves on the shelf but you have 100 French baguettes, people assume it’s a weird, exotic thing. But if you can sell a little more, you can make a little more, and then people see more of it on your shelves, and they think, ‘Oh, that’s normal, I can have that.'”

Increasing rye’s profile in America isn’t just a matter of getting people to try something new. Every baker contacted for this article agreed that rye bread is much trickier to make — and therefore easier to make incorrectly. You practically need a chemistry degree to understand all the elements involved — a discussion of rye baking quickly gets overloaded with terms like acidification, enzymes, glutens, amylase activity, and starch-to-sugar conversion — but the short version is that rye dough is much stickier and more difficult to handle, and is very susceptible to being overworked. So it’s a much bigger challenge for a baker.

“I think if we can train bakers to make these things correctly, that’s going to trickle down to their clientele,” Mr. Hamelman, the King Arthur bakery director, said. “I teach a baking class myself, and I can’t tell you how much my students adore the 90% and 100% rye breads, because it’s so good. So if it’s done right, people will definitely accept it.”

As for deli rye, its place in New York’s bread pantheon is still secure. After all, we’ll always need that big, broad slice to accommodate an overstuffed pastrami sandwich.