The bakers at Diamond City Bread in Elk River joke that they keep their dough in a bank vault. But maybe they're not kidding.

The basement bakery -- which specializes in sourdough bread and supplies loaves to co-ops, restaurants and farmers markets from the Iron Range to Winona -- is housed in a building that once was the Bank of Elk River.

Any place else, a bank vault within a bakery would be the main topic of conversation. But here, it's the sourdough.

"Sourdough is our specialty," said Garrett Jordahl, who has been baking at the store since its inception in 1996 and now owns it. "It's a lot more work because you have to have sourdough culture. ... It takes time and patience.

"Sourdough breads ferment -- 20 to 22 hours. That's a long time, but our customers seem to appreciate it."

One drives all the way from Forest Laket for a loaf of sourdough, Jordahl said. Another told Jordahl drives nearly six hours from northern Minnesota to buy a dozen loaves.

Even in the heart of Elk River's quaint, downtown business district, it's not the easiest place to find. Below sidewalk level, in the middle of Jackson Street, lie Diamond City's gems.

The daily breads include sourdough, 12-grain, honey wheat and white. Then there are the daily specials: tomato garlic basil, wild rice blue cheese, green olive mozzarella, parmesan pepper, roasted onion rosemary, you name it.

"We have to be different and we have to be creative," said Jordahl, 41. "Every grocery store with a bakery has an acceptable product. It became clear, early on, that I had a natural ability. I'm using every ounce of that."

Diamond City Bread was started by Frank Galli, a corporate salesman who wanted to try something different. Galli, who owns the building, also owns Pompeii Pizzeria upstairs.

"I just wanted to open a small business," Galli said. "It's a real neat building, the original Bank of Elk River, built in 1915."

He needed a head baker. Jordahl was baking for Nelson Bros. Restaurant & Bakery in Clearwater, making pies and rolls. His wife, Angela, was returning to school, and Jordahl was looking for more work.

Galli offered more than that. He offered Jordahl a partnership. Galli eventually left the business (while keeping the building). Diamond City Bread went through two ownerships before Jordahl purchased the business in 2005.

When farmers markets in Annandale, Monticello, Champlin, Rogers and Becker began featuring his breads, word and aromas spread. Jordahl hired other bakers and marketed breads in co-ops and natural-foods stores in Anoka, Cambridge, Winona, Virginia and Grand Marais, Minn. Restaurants began approaching.

"The hard work was getting our products out there," Jordahl said. "The baking is exciting, even after all these years. Who knows what we might create tomorrow?"

Paul Levy • 612-673-4419