By John Arena

While Italians may rightfully claim to be the originators of the dish that we have come to know as pizza, there can be little doubt that the United States has developed the most diverse expressions of this culinary mainstay. This is a result of many factors, including cross-cultural influences, creativity and the vast array of ingredients and equipment available to ambitious American pizza chefs. Students of the pizza-making craft have felt free to experiment and innovate so that the U.S. now has dozens of identifiable pizza-making styles that co-exist side by side.

Some chefs would claim that there are as many pizza styles as there are people who make them. However, the dominant popular forms can be identified by some basic key elements, including dough type, stretching and shaping method, sauce and spice profile, cooking methods and topping variations.

In the past, most of these regional styles could only be found in their places of origin. However, today, each of the styles have adherents throughout the country.

Here’s a closer look at nine of the most famous pizza styles found in the U.S., from the classic New York-style to the Philly tomato pie. For information on other styles, check out the article links throughout this story.

1. New York-Style Pizza: This style, the most popular form in the U.S., features a classic thin crust. The basic dough uses high-gluten bromated flour milled from wheat primarily grown in North Dakota and Minnesota. Fresh yeast is used and long fermentation times are employed to create flavor and texture. Olive oil is added for enhanced flavor and to prevent the sauce from penetrating the dough.

This pizza is typically hand-stretched to order, with a minimum size of 16” in diameter and a pronounced rim. The smooth, thin tomato sauce is made from sweet, vine-ripened California tomatoes and can be seasoned with oregano and occasionally thyme. High-butterfat, low-moisture shredded mozzarella cheese from Wisconsin is preferred, and an additional light sprinkle of imported Romano cheese may be added after the pizza is baked. Typically, this pizza will be cooked directly on the stones of a gas-fired oven, with many pizza makers claiming that older stones are superior.

Related: What are the elements of an authentic Detroit-style pizza?

2. New Haven-Style Pizza: This one is loosely based on the pizza of Naples. Local residents use a dialect-based pronunciation, always referring to this type, called apizza, as “ah-beetz.” The dough recipe uses medium-protein all-purpose flour and a high percentage of water. This formulation results in loose dough that is hand-stretched on a marble table. The dough is usually too soft to pick up and is simply flipped onto the pizza paddle before being slid into a coal-fired oven, which produces a crispy yet tender crust.

Typically, these pizzas are irregular in shape and distinctively charred. The sauce is similar to the New York style but may include fresh garlic. Cheese can be a combination of low-moisture mozzarella and New England cheddar; however, these pizzas tend to use light amounts of cheese. New Haven is famous for the clam pizza, which uses only olive oil, fresh clams and oregano without any cheese at all.

3. Mountain or Western-Style Pizza: This style has been influenced by the climate and active lifestyle of its residents. The dough is formed using warm water and fast-acting yeast. Whey or milk will often be added for a mildly sweet dough, or recipes will include a sourdough starter. The crust is medium to thick, with a pronounced rolled edge.

The Mountain-style pizza is topped with a relatively light amount of thick, tangy sauce that is seasoned with oregano, thyme, dry basil, marjoram and granulated garlic. It’s covered with large amounts of part-skim California mozzarella cheese, sometimes mixed with yellow cheddar. Pepperoni is the most common topping, but more exotic local ingredients may be added, such as ground American bison meat.

The pizzas are baked on wire racks in conveyor ovens and are usually cooked lightly, with no distinct charring or blistering. In colder climates, this pizza will be served with a side order of honey for dipping the crust.

Related: Compare and contrast: Old Forge-style pizza vs. Sicilian pan-fried pizza

4. Southern New Jersey-Style Tomato Pie: This one, on the surface, appears similar to the New York style; however, there are several distinct differences. Typically, the dough formulation will not include olive oil. While the hand-stretching method is done as in the New York style, this pizza is topped with locally produced shredded mozzarella before the sauce is applied. The sauce is smooth but thicker than New York-style sauce and is splashed on the pizza randomly, with Romano or domestic Parmesan cheese added on top. The “cheese-first” method produces a crispier crust with creamier melted cheese. Traditional toppings are anchovies or sliced sausage that is precooked and then distributed on the pizza before baking.

5. Chicago-Style Thin-Crust Pizza: This one is sometimes referred to as “tavern pizza.” The dough is made from all-purpose flour and contains a low water content and a high percentage of vegetable oil. Fast-acting dry yeast is preferred, with short fermentation times. The dough is never hand-stretched but is instead rolled using a rolling pin or a mechanical dough sheeter in high-volume restaurants. This method produces a flat tight crust with no raised edges.

Chicago thin-crust pizzas are topped with a tangy, thick tomato paste that has been heavily seasoned with oregano and granulated garlic. All toppings are placed under the shredded mozzarella cheese. Raw sausage removed from the casing is the most common topping. The pizzas are baked in a rotating or carousel deck oven at relatively low temperatures. This method produces a cracker-like crust. The pizza is cut into small squares before serving.

Related: Why we’re mad about Milwaukee-style pizza

6. Chicago-Style Deep Dish: This one is often considered a Chicago creation, but it’s actually a variation of the savory holiday pies first introduced to Southern Italy by Albanian refugees in the 15th century. The rich, biscuit-like texture of the crust is achieved by using winter wheat flour from the American Midwest mixed with a high percentage of shortening and sometimes aided by the inclusion of cornmeal or semolina. A small amount of beer may be included in the mix to create more complex flavors and aroma.

The dough is pressed into heavy, high-sided, black steel pans that have been coated with oil, shortening or butter. This pizza gives the appearance of having a thick crust because the dough has been shaped up the side of the pan. However, it should not be confused with thick-crust pizza. The dough is allowed to rest in the pan for 15 minutes or more, and then it’s filled with layers of mozzarella, toppings and a covering of a smooth or crushed tomato sauce that is seasoned with oregano and domestic Parmesan and sprinkled with olive oil. The most common toppings include fennel-flavored sausage, pepperoni and cooked spinach seasoned with nutmeg. The pizzas are baked in deck or carousel ovens at 425° for up to 45 minutes.

7. Philadelphia-Style Tomato Pie: This one is similar in name to the New Jersey pizza, but it’s actually quite different. The dough is made from all-purpose flour, allowed to ferment, and then stretched and placed in a square black steel pan coated with olive oil or baked directly on the stones of an oil-fired oven. A light sprinkle of shredded mozzarella is generously covered by a chunky, slow-simmered sauce that contains yellow onion, fresh garlic and a large amount of extra-virgin olive oil. The pizza is topped with grated Parmigiano-Reggiano before baking.

Related: The story of Ohio Valley-style pizza

8. California-Style Pizza: This style, a fusion of Asian and classic European techniques, was developed in the 1980s and usually features organic, locally grown ingredients. Typical dough formulas will use organic unbleached bread flour often combined with honey or sugar to produce a chewy, pliable crust. The pizzas are hand-stretched with a pronounced rim and do not exceed 12” in diameter.

Wood-fired ovens, often using aromatic woods such as mesquite or hickory, are preferred, but gas-fired open-flame brick ovens will be used when local ordinances prohibit the burning of wood. Toppings are selected in accordance with seasonal availability. Noticeable Asian influence can be seen in the use of fresh, lightly cooked vegetables that retain beautiful color and texture. Great emphasis is placed on the balance of flavors and texture. A wide variety of locally produced artisan cheeses are employed in combination, including cow, sheep and goat milk cheeses.

9. “Old New York” Coal Oven-Style Pizza: This style is often marketed as the original style of Italian-American pizza, although this claim is highly debatable. Origins aside, the coal-fired method can certainly produce unique and delicious pizzas. The dough is made from American high-gluten flour, water, salt and fresh yeast. Pizzas are thin and hand-stretched, with a small raised edge that becomes very charred and blistered from the intense heat of the oven.

The sauce is made from San Marzano crushed tomatoes, and each pizza is individually seasoned with oregano and Romano cheese. Pizzas are topped with thin slices of cow-milk mozzarella from New York State that’s specially formulated with slightly lower moisture content than traditional buffalo mozzarella or fior di latte. Raw vegetables are never placed on these pizzas; instead, most toppings are pre-roasted in the coal ovens before being added. Hand-sliced pepperoni with a high fat content is prized for its tendency to char, cup and release flavorful oils on the pizza.

Related: Wagner’s Pizza Bus serves 30 regional styles in wild Alaska

The baking time for coal-fired pizza can be as short as 90-120 seconds. This type is rarely sold by the slice, and the pizzas never exceed 18” in diameter.

By becoming familiar with all the major regional pizza styles, you can add your own experiences and originality, transcending the current forms and adding to the larger body of knowledge for the next generation of pizza makers and pizza eaters.

John Arena is a third-generation pizza maker with more than 50 years of experience. He is the co-founder of Metro Pizza in Las Vegas, which is known for serving a variety of pizza styles. This article originally appeared in the May 2010 issue of PMQ.