One of the half dozen pizza ovens at Tony's Coal-Fired Pizza & Slice House in San Francisco.
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Heat Blisters

Merrill Shindler / July 2012

Merrill Shindler investigates the whys and wherefores of great pizza ovens.

The standard
When most of us think of tissues, the name that comes to mind is Kleenex. When we think of wiggly, brightly colored desserts, it’s Jell-O. And for those who make pizzas for a living, for the past two decades the iconic name of choice is Wood Stone. Not bad for a company founded on a shoestring by a kitchen equipment salesman, and a guy who built incinerators for a living—masters of the adage “Find a Need…and Fill It.” Wood Stone founders Keith Carpenter and Harry Hegarty did what only a precious few have managed in history—they actually built a better mousetrap. And truly, the world beat a path to their door.

It was back in 1989 that Carpenter went on what he describes as a “routine call” to a customer in the Pacific Northwest, who told him he was having a hard time finding a wood-fired stone hearth—a brick oven—that he could use in his commercial kitchen. There is a history of brick ovens in much of the world—the stone hearth goes back thousands of years to the earliest cooked foods. There is evidence that woolly mammoths were roasted in stone hearths 25,000 years ago. But in America, the brick oven had faded from use over the years, in many cases the victim of increasingly draconian ventilation laws. In too many communities, car exhaust is OK, but wood smoke from an oven isn’t.

The customer’s lament kindled a fire in Carpenter. He decided to find a way to build a brick oven that would work in America. His research led him to Hegarty, who had been building large-scale, high-temperature ceramic incinerators for the forest products industry for the previous 17 years. Carpenter says, “Harry is an amazing guy. He won’t let me call him an engineer. But what he learned from building high-heat incinerators, which are a lot like our ovens—only larger—is what made the difference. You bring Harry something and say, ‘I want something like this, only better.’ And that’s what he did.”

They began discussing brick ovens in 1989. In 1990, they founded Wood Stone—or at least, what would eventually become Wood Stone. “In the early days,” says Carpenter, “we didn’t have a lot of people. There were just three of us, and we had regular jobs. We’d work in Harry’s shop. But at night and during weekends, we’d push the incinerators to the side and start casting ovens.” Slowly, they began finding clients. But since the clients ran functioning restaurants during the day, Carpenter, Hegarty, and friends had to do their work at night. “We’d bring all the pieces in and assemble them. It was like building an igloo. We’d work all night—and in the morning, there’d be an oven.”

Wood Stone was a niche company, supplying classic ovens for pizzaiolos with a commitment to doing things the old way—sort of Slow Food before there was Slow Food—until the watershed year of 1993, when two culinary institutions changed the company forever.

One of those institutions is Wolfgang Puck, whom Carpenter met at the Kaiser Grille, a restaurant in Palm Springs, California, that had installed a Wood Stone for its pizzas. Puck was catering a nearby event. He dropped by the Kaiser Grille at about midnight to give the Wood Stone oven a try. According to company history, he told Carpenter he “had never seen an oven that cooked pizza crusts as evenly as the oven at Kaiser’s.”

At the time, Puck was using a variety of ovens in his restaurants. After the test, he went totally Wood Stone; he’s installed more than 70 to date. And he gave the company what may be its most powerful endorsement: “If I could only have one piece of cooking equipment in my kitchen, it would be my Wood Stone oven. I’ve used a lot of ovens. And Wood Stone is by far the best in its class.” You can take an endorsement like that straight to the bank.

The second institution was the California Pizza Kitchen. It was also in 1993 that CPK asked Wood Stone to help with the branch they had opened in the Mirage in Las Vegas. The first oven they had installed there (not Wood Stone) had suffered a “degradation of the oven floor called spalling,” thanks to the extremely high volume of pizzas ordered at the casino. The replacement was becoming “compromised” as well. And so, in 1993, Wood Stone put in CPK’s third oven. It’s still there to this day, cranking out 1,000 pies per day—and 1,400 to 1,500 on especially busy days.

With that success, Wood Stone became CPK’s main oven supplier, with more than 200 installed worldwide. But as they say, “the story doesn’t end there…” After purchasing some 75 wood-fired ovens, CPK asked Carpenter if gas-fired ovens were a possibility.

Carpenter says, “We were skeptical of the concept. But because CPK was insistent, we listened.” They started experimenting with gas-fired ovens in 1994. In 1995, they installed their first—at the CPK in LAX in Los Angeles. Then, they installed one in the CPK in Boston. Today, the majority of Wood Stone ovens are gas, rather than wood. Carpenter says with a shrug, “Y’know, we’re Wood Stone, not Gas Stone.” Life’s funny like that.

He also admits, “We learned to love it ourselves. We learned it’s not important how you get the ovens hot. It’s this huge ceramic stone platform that matters the most. And now we’re dealing with a resurgence of coal—we’re making coal-fired ovens. I have to say, we’re reluctant about them. Coal does do a great job—but there’s a perception that it does the best job. We have 40 or 50 coal ovens on the market. It’s a marketing tool more than anything else. There are fantastic pizzerias cooking with coal. But coal is a difficult fuel source to manage. Is it the coal, or just good pizzaiolos who make the difference? As far as we’ve found, it’s having an open flame and a stone hearth—that’s the magic combination.”

To date, Wood Stone has sold more than 9,000 ovens in 70 countries around the world. They’ve created specialized deck ovens for China, tandoor ovens for India, and pita ovens for Saudi Arabia. But they have yet to sell their first oven in Italy. Which is funny—since the Italians have used their ovens, and (reluctantly) they admit, they like them.

Carpenter says, “It took a while for the Italians to accept that we could build a good oven in America. It began with the International Pizza Expo in Las Vegas, maybe the most important pizza show in the world. It’s filled with Italian purveyors. Caputo, the flour maker, is always there; they make the best pizza flour in the world. Eight years ago, they first went to the pizza show. They had three wood-burning ovens they had brought from Naples. But they couldn’t use them in the convention center. So we loaned them an oven. They didn’t want to use it. They didn’t want to use gas—but it was all they could use at the show. And by the end of the show, well—they were in love. The oven wasn’t even round—it was square. But it worked beautifully for them. Since then they’ve used our ovens at every pizza show. And you know, of the 58 American restaurants approved by the Verace Pizza Napoletana, 15 use Wood Stones. We’ll have ovens in Italy one day.”

The standard…and friends
Where they do have an oven right now is in the little bit of Naples opened by Guinness Book of Records’ pizzaiolo Tony Gemignani. (He’s in for spinning a 36 1/2 inch pizza continuously for two minutes…and for 37 pizza dough “shoulder rolls” in 30 seconds.) Gemignani—who’s also the Association Pizzaioli Napoletani’s U.S. Ambassador of Neapolitan Pizza—runs a pair of adjacent shops in San Francisco’s North Beach—Tony’s Pizza Napoletana next door to Tony’s Coal-Fired Pizza & Slice House.

They connect through the kitchen. And it’s on the Slice House side that they’ve got the coal-fired Wood Stone Model 9660, which pizzaiolo Eric Corbin explains is used to create the perfect New York–style pizza. “True New York pizza is coal-fired. And that’s what’s coming out of this oven. It was tough getting a permit. But anthracite burns clean, so we got it through. A barbecue in the backyard will put out more smoke by far. Anthracite is the cleanest burning fossil fuel. It brings the oven up to about 1,000 degrees. Takes two and a half hours to get it up to temperature. And then it stays there all day.”

The Wood Stone is one of half a dozen ovens in the two shops, each temperature-specific for different types of pies. On the Napoletana side, the first oven you see looks like a brick igloo with a fire burning in it. Corbin says, “Tony won this oven years ago. It’s a Forni Cirigliano. But it’s been used so much the name rubbed off long ago. It burns oak and almond wood—oak burns hotter and almond creates the dome flame. We use wood chips, too, to get the temperature in the dome high enough. It’s got to be 900 degrees to make a proper Margherita, which takes about 90 seconds to cook. We make just 73 San Felice Margheritas a day—that’s the rule. It’s a true Neapolitan—real old, a beautiful oven.” (For the record, it’s the pie that won the World Pizza Cup in 2007 in Naples. That’s right—an American won the cup. The Italians are still in denial.) Walk around the pizzerias, and there are ovens everywhere: A Cuppone electric pizza oven—“600 degrees, we cook our classic Italian pizzas, and our pizza Romana, really thin, three different toppings.” A Marsal & Sons gas oven—“it’s where we cook a lot of American pizzas in the top section, and French rolls, ciabatta, focaccia, all down here in the lower section. We make a Cal-Italia pie in the Marsal, with mozzarella, Gorgonzola, Asiago, fig preserves, balsamic reduction, and prosciutto di Parma.”

There’s a Bakers Pride for gluten-free pizza. There’s a Roto-Flex deck oven—“a real workhorse, three decks rotating about 520 degrees…we sell the pizza from the Roto-Flex by the meter.” Why so many? Simple—as Mr. Natural used to say, right tool for the right job. Or as pizzaiolo Corbin says, “We have seven different dough recipes. And each needs a special temperature. Our goal is simple—the perfect pizza…in the perfect oven.”

If you build it, they will come
Had Henrik Ibsen lived a century later than he did, he might have written his drama, The Master Builder, about a man who constructs pizza ovens, rather than “castles in the air.” For the master builder of the Forno Per Pizza is regarded in Italy as a holy soul—a builder touched by the hand of the Lord. Or at least, the hand of the panettiere.

One of the most desired of these master builders is Neapolitan pizza oven designer and builder Stefano Ferrara, a man for whom building ovens runs like marinara in his blood—both his father and his grandfather built ovens that were (and are, for pizza ovens last for generations) culinary objects of desire—and works of art.

Chefs Steve Samson and Zach Pollack became enamored of Ferrara’s oven while touring the pizzerias of Naples, researching their Los Angeles restaurant, Sotto. “The best pizzas we ate came from Ferrara-built ovens,” says Samson. And so, they decided they had to have a Ferrara—and not just one shipped over and assembled by a local craftsman. They had to have a Ferrara hand-built on-site by Ferrara himself. They imported 15,000 pounds of bricks and stone and refractory cement and sand from Vesuvius—and the oven builder himself—seven wooden palettes of material (not including Ferrara and his assistant, who came on foot).

The Ferrara oven took a week to build and an additional 10 days of constant careful heating to begin the drying process. (The full process takes a month.) Ferrara also builds the restaurant’s name, in tile, into the top of the oven’s dome, where it proudly proclaims “SOTTO”—the first pizzeria in Southern California to cook its pies on the Ferrari of pizza ovens. Others can be found at Eataly in New York City, Paulie Gee’s in Brooklyn, Pizzaiolo Bavaro in Tampa, Florida, and Via Tribunali in the Pacific Northwest. And if you’re in Naples, stop by Antica Pizzeria Regina, D’Italia Brandi, Il Pizzaiolo Del Presidente, Spaccanapoli, or Anema E Pizza—all home to Ferrara ovens. Master builder Renato Riccio works out of Dallas. But his roots are as Italian as Stefano Ferrara. As a child in Tuscany, he worked as a brick layer. At the age of 20, he headed for America with $3 in his pocket. After several years working in restaurants, he saved enough money to import a wood-burning brick oven from Italy. He opened a restaurant called the Bel Air Grill, offering the first pizzas baked in a wood-burning oven in Dallas. In 1981, he opened Renato Ovens, Inc. He says, “The phone hasn’t stopped ringing since.”

Phoenix pizza legend Chris Bianco began his wood-burning career with a Riccio oven. He says, “I had my first wood-burning oven built for me by Renato about 20 years ago. It was a little difficult. Renato was still new in the business. I didn’t really know what I was doing. But I had this image. I had seen some old bread ovens in Pompeii. They had essentially the same design as pizza ovens today. Nothing had really changed. I had been making my pizzas in a Bakers Pride oven. It made a beautiful pizza. I made wonderful focaccia at home in my kitchen oven. But I wanted something that was classic. And Renato poured me a beauty.”

Bianco says, “The genius of great oven makers is they know how to insulate, they know how to create an oven that maximizes the heat, and holds the heat. The oven is no more important than any other part of the process—even the paddle is important. But if the oven isn’t doing its job, nothing else matters. It may just be a tool—but it’s got to be a tool that works.”

Or, you can just do it yourself
As the old expression goes, if you want something done right, do it yourself. Though when it comes to pizza ovens, most of us would draw the line. But not Frank De Carlo, chef/owner of Peasant in New York City’s NoLita (North of Little Italy) neighborhood. He spent some time studying classic pizza oven design. And decided that it couldn’t be that hard to build.

De Carlo, who speaks with a New York accent as thick as mozzarella, says, “It’s really pretty simple to do. It’s like building an igloo. First you build the frame, like a dome. You have to use thin wood, so it’s malleable. Plywood is good. Then, you have to use support bricks, and make sure they settle, so it won’t crack.

“The toughest part was getting the bricks. Old bricks cost a fortune. So, I pulled bricks from a construction site. The hardest part was getting the flue right. You’ve got to get the updraft right or it’ll fill the kitchen with smoke. I worked on that for a long time. But I always had a good feeling about it all. It felt natural, like something they got right a long time ago, and it still works. We’ve been using it for 11 years now—no problems at all. My wife likes it so much, she wants me to build one for us at the place we have out on Shelter Island. I’d like to do that. But who has the time?”

And just in case you want to build your own pizza oven, you’ll find instructions all over the Internet. Go to sites like,, and even, where they’ll sell you a book that tells you how. Or just call Wood Stone—and support the pizza oven company that even the Neapolitans like.