For serious pizza aficionados, pies cooked in a coal-fired oven rank above all others.
There are dozens of Internet discussion forums debating the merits of 1,000-degree heat and the proper amount of char for a pizza crust. Stories abound about pizzaiolos who trained for years before ever being allowed to touch the peel.
There's even a page on the pizza blog Slice devoted to mapping the location of every coal-fired oven in the country. Interest in coal-fired ovens, barely on the radar screen for most people several years ago, is now top of mind for pizza lovers.
"Until about four years ago, we probably got one or two calls a year about coal-fired ovens, and then all of a sudden it was like the sky was falling," said Frank Milward, corporate chef at the Bellingham, Wash.-based oven manufacturer Wood Stone. "I would say that now I talk to a new person interested in coal almost every day."
Milward attributes much of the interest in coal to celebrity chefs who got into the pizza business focusing on Pizza Napolitana, or Naples-style pizza. Many of those chefs looked to the history of pizza in North America for inspiration.
"There's always been lots of talk about pizza in the Northeast; places like Lombardi's, Pepe's, Patsy's and Grimaldi's," he said. "Lombardi's was the first pizzeria in the United States, and it happened to be coal-fired. So for today's chefs, going forward was looking back."
Interest in coal-fired ovens continues to grow. Despite the allure of coal-fired ovens, though, operating one is not for the novice.
"Coal is cantankerous and it requires paying attention," Milward said. "Great food hurts."
Difference is in the bake
One of the differences provided by the use of coal comes not from the coal smoke but by the intense heat a coal fire generates, said Keith Carpenter, president of Wood Stone. Coal provides about 13,000 BTUs of heat per pound, while wood provides about 6,500 BTUs per pound.
Because oven temperature can top 900 degrees or more, pizzas generally cook in two or three minutes.
Issues with operating a coal-fired oven range from maintaining the proper amount of heat in both the chamber and the oven floor to proper ventilation and the proper type of coal. Plus, bringing a coal-fired oven to proper operating temperature can take 90 minutes or more.
Most coal-fired oven operators recommend using only anthracite coal, which contains fewer impurities and is cleaner burning than other types of coal. Anthracite, which is mined primarily in Eastern Pennsylvania, is difficult to ignite but burns with a blue, smokeless flame.
Chuck Senatore, operator of Tony Sacco's Coal Oven Pizza, opened his first pizzeria in Naples, Fla., a year ago. Like many others in the business, he first encountered coal-oven pizza in the Northeast.
"The coal oven gives you a bake that you can't get anywhere else," he said. "It requires more skill in cooking, but it gives you a far superior product. People can really taste the difference."
Senatore's morning routine starts with building a fire using wood and garden variety grilling charcoal. That fire is then used to ignite the coal. At the end of the night, the oven is cleaned out and any remaining live coals are kept for the next day's fire.
Not only is coal a great fuel for cooking pizza, it's a great marketing angle, he said.
Even so, there was an education process that had to occur, both for Senatore and for his customers. While native New Yorkers might appreciate the smoky flavor of a charred, slightly blackened crust normally associated with coal-fired pizza, others don't always feel the same.
"When we first started, we were cooking our pizzas a decent amount and giving them a little char, and people didn't care for them that much," he said. "We backed off a little bit on our bake. We make it known to our customers that if they would like it cooked a little more, we can do that."
Joe Ciolli, whose family owns the legendary Grimaldi's pizzeria under the Brooklyn Bridge in New York, encountered a similar situation when he opened a Grimaldi's location in Phoenix. He now operates Grimaldi's in Arizona, Texas and Nevada.
"There were a lot of people who thought the pizza was burnt because of the way the crust looked," Ciolli said. "The biggest problem we had was making the pizza more conducive to people on the West Coast. It took a while to get people to understand it."
According to Milward, though, great coal-fired pizza comes not from the oven itself but the skills the pizzaiolos develop working with the oven.
"The more you have to build a relationship with the chamber you are in front of, the better your pizza becomes," Milward said "By the time you master consistently managing the temperature in a chamber with coal, the intricacies and the commitment of doing a great pizza have already come."