Kevin Sousa is crouched down with a Wagner power painter, spraying thickened vanilla milk into a bath of liquid nitrogen and turning the pure white liquid into a mass of bubbling crystals.

	Doug Oster, Post-Gazette Kevin Sousa, chef at the Bigelow Grille in the Doubletree Hotel, Downtown, prepares "Blue," a cotton candy-like dish for his menu called Alchemy, which combines science and food preparation. Click photo for larger image. Restaurant Review: Culinary alchemy: A revolution in the kitchen

T his isn't a chemistry experiment in a laboratory; he's creating one of the 25 courses of his revolutionary new menu called Alchemy at the Bigelow Grille, Downtown. The 31-year-old chef is preparing his latest addition to the menu, simply called "Creamsicle." He pauses before tasting the steaming ice crystals.

"It's weird blowing on something to get it warm," he says.

Although the restaurant has a typical menu for "normal" diners, foodies can embrace a second menu based on molecular gastronomy, or the application of scientific methods to food. The idea originated with French scientist Herve This and Hungarian physicist Nicholas Kurti, who began experimenting with those methods in 1969.

Mr. Sousa uses food chemicals that come from natural sources, such as seaweed and salt derivatives -- alginates, for instance, that are extracted from seaweed or kelp and help turn liquids to solids -- to transform food.

"What they allow us to do is to take a fine-quality raw ingredient and manipulate the texture, the appearance, and it creates a new experience," he said.

Mr. Sousa's kitchen is filled with some of the most incredible and unusual ingredients ever seen in a cook's pantry. Cocoa and wasabi share space with calcium chloride and silicon dioxide. Sage and coconut are flanked by xanthan gum and sodium citrate.

Then there's the weird lab equipment: syringes, slender plastic pipettes and even a little pink cotton candy maker that looks as if it might have been sold with an Easy Bake Oven. But everything here is safe to eat, carefully chosen as food-grade additives.

In the hands of Mr. Sousa, they are unexpectedly delicious. For one dish, the kitchen is filled with the scent of burning rosemary as he fills globular glass beakers with the herb's smoke. Guests squeeze a little puffer to release the smoke, and at the same time take a bite of food off the top of the globe, mingling aroma and flavor.

"It's scientific in that we use scientific ingredients and methods, we're using blow torches and liquid nitrogen, we're carbonating fruit," he said.

Mr. Sousa began this culinary journey growing up in the kitchen of his family's restaurant, Sousa's, in McKees Rocks. After high school, he explored Europe and traveled across the United States, spending time working in pizza parlors and hoagie joints.

Where now he runs a spotless kitchen, often washing his hands between each course like a doctor between patients, he once stood over a deep fryer slinging fries along the Jersey Shore.

"I was always interested in food, eating sushi, eating food that was strange to other people," he says.

In 1999, he graduated at the top of his class from the Pennsylvania Culinary Institute, and was hired for his externship at the Boulders Resort in Arizona. After two years there he returned to Pittsburgh to work at the Duquesne Club, Downtown. He then moved to Soba in Shadyside, part of the big Burrito restaurant group, and eventually worked stints as executive chef at Kaya in the Strip District and then back at Soba.

When he saw an ad in the paper looking for a chef to start a new restaurant, he jumped at the chance and opened the Bigelow Grille a little more than a year ago.

It was in Arizona that he became fascinated with the cooking of Ferran Adria of Spain, who pioneered many of the techniques he uses today.

"I'd seen avant-garde food, but it was mostly classical French techniques applied to really cool presentation, whereas Ferran Adria was creating new techniques that lent themselves to new presentations. He was creating new foods."

The Alchemy menu is Mr. Sousa's, but he pays homage to his idol with such dishes as Split Pea and Beets, which both use Mr. Adria's seaweed extract hardening technique. Some of Mr. Adria's influences are apparent in the way the courses are arranged on the menu.

"We kind of break up a meal in ways that a lot of other people don't. We put sweet where you don't expect sweet, textures you don't expect. Just trying to give people a meal that flows differently."

To create his menu, Mr. Sousa needed information and inspiration. He asked his general manager at Bigelow Grille to send him to Chicago to learn what other great chefs were doing. The chef ate out every night, learning with each bite.

The dinner at Alinea provided an epiphany.

"The food was very sensory, and it was fun. It was fine dining, but it wasn't stuffy. The service was relaxed and comfortable. We laughed and drank. That meal changed my life culinarily. It blew me away. I want to create an experience like this for people in Pittsburgh."

When he returned, he showed what couldn't be told -- there's no explaining this type of food, he thought to himself, it just has to be tasted.

He and sous-chef Robert Sayre used trial and error to create their dishes. At each step, they would offer their unusual creations to friends, people in the business and anyone they thought would "get it." Sometimes it took five or six attempts to reach what they thought was perfection, just to continue to work to make the recipe even better.

Word got out that Mr. Sousa was doing something radically different yet delectable, and the underground network of food lovers and restaurateurs took notice. Then, one day, Mr. Sousa saw his name next to that of his idol, Ferran Adria, on Wikipedia, thanks to bloggers who had visited his restaurant.

Tina Kelsey of southern Ohio travels a lot to eat, and a friend brought her to the restaurant on a recent visit to town. She was intrigued with the first course, but the second dish convinced her it would be a night to remember.

"The blue thing [cotton candy] won me over. I loved the food in the tube, too -- that was just big fun," she said.

Chris Jackson, executive chef at Six Penn Kitchen, is also a fan of Mr. Adria and had a chance to sample the Alchemy menu. Although he enjoyed his meal, he wonders about the longevity of molecular gastronomy. "I give all the chefs their due; it's incredible science. In the same breath, I don't know if it's just another phase or something that's the next big turn in the culinary world."

Mr. Sousa thinks these techniques will thrive and is passionate about what he's accomplished. "It's been said that to create new experiences, new flavors and new textures, you need new techniques.

"You can't just be stuck on sauteing, grilling, poaching and braising. There are other ways to cook, and this has a lot of staying power."