For physician Jeff Hertzberg and baker Zoe Francois, the journey to no-knead bread began innocently enough.

While their toddlers learned to play the xylophone in a Minneapolis music class, Hertzberg began telling Francois about his no-knead, 5-minute mix of flour, salt, yeast and water.

Made in large batches, the dough can be refrigerated for weeks and baked one loaf at a time by simply cutting off a piece, letting it rise, shaping and baking. Trained in traditional methods, Francois was skeptical, but she saw promise in the chemistry Hertzberg was selling: A wetter-than-average dough that was easier to handle and simple to work with.

Now, the duo have released their second book on no-knead bread, joined by tomes from two fellow bread pioneers.

Bread has followed a rocky path in American culture of late. Demonized during the low-carb craze of the 1990s, bread resurfaced as the darling of the artisanal movement. The desire to have those fancy and healthy loaves at home spawned interest in low- and no-knead bread baking methods.

"I think there is a real interest lately in do-it-yourself projects, and bread falls in that," said Karen Bornarth, head of the bread department at the French Culinary Institute in New York. "Supermarket breads or commercial breads, if you read the labels, they are filled with preservatives. There are not a lot of bakeries out there. Bakeries are dying. So if (people) want good bread, they have to make it themselves."

Trained at the Culinary Institute of America in Hyde Park, N.Y., Francois embraced Hertzberg's method after checking it out herself.

"When I tried it, it really was revolutionary, and was mind-boggling because it went against everything I had been taught," she said. "Everybody had to know about this."

The first book from the two, "Artisan Bread in Five Minutes a Day" (Thomas Dunne Books, 2007), was well received and has 200,000 copies in print. This month, they release "Healthy Bread in Five Minutes a Day." Two other no- or low-knead bread bakers also put out books in October: Jim Lahey with "My Bread" (W.W. Norton & Co.) and Peter Reinhart (who pledges ease more than outright no-knead) with "Artisan Breads Every Day" (Ten Speed Press).

To those counting the minutes, no-knead bread doesn't really take just five minutes. The reference refers to the time it takes to mix ingredients, not taking into account resting time and baking. But critics and proponents agree it's a vast improvement over the laborious process of making artisan breads using classic methods — kneading and rising, with starters to consider for sourdough or rye.

"I am fine going on record saying this five-minute thing is silly," said cookbook author Mark Bittman. "It's just marketing, but it doesn't detract from the fact that it is a good technique and a good idea. I think to the extent that you can take kneading out of breadmaking, it's great. Kneading is a mess."

The books all preach the same basic principles: Make it simple.

"The books are accessible to people who have never baked bread," Hertzberg said. "The key to our books is that if you don't teach people how to store it, they are not going to do it often. It's giving people the freedom to create a bread that fits in their diet or the way they eat."

In their new book, Hertzberg and Francois have gone one step further, meeting the needs of people who have approached them about baking breads that use less sugar, healthy grains, fruits and vegetables, and are friendly to those with allergies or food sensitivities.

Figuring out how to simplify healthy breads is exactly how Hertzberg and Francois have spent most of their free time during the last year. They live in southwest Minneapolis across from each other on Lake Harriet. Each spends a good part of their day baking several loaves. For both books, they have used the same trial-and-error method, simplifying without compromising quality.

For healthier breads, they agonized over how to incorporate spelt flour, which is lower in gluten. They struggled to figure out how to substitute for the fluffiness of eggs and the right amount of canola oil needed to replace butter.

The way the bread feels in the mouth was of primary importance.

"In this book, we wanted to have that same sensation, but have it be healthier," Francois said.

To achieve taste and feel for gluten-free breads, for example, Francois turned to xanthan gum, which "mimics the gluten."

"To try and get those flours to mimic what people want in a mouth feel was a challenge," she said. "It was a lot of sleepless nights and frustration, and then we got it."