Pizza styles differ depending on where you are. If you walk into a pizza restaurant in New Haven, you will get a much different slice of pizza than you would in New York City. That said, here are 4 famous regional styles to familiar yourself with.
New Haven Style
In New Haven, pizza is made with only oregano, tomato sauce and some grated hard cheese (such as pecorino romano.) Unlike a NYC or Chicago style, mozzarella is considered a topping, so you have to order it like you would pepperoni or mushrooms. This sauce, oregano and hard cheese style is known as a "plain."
The other type of popular New Haven pizza is the white. It's different from NYC based white pies (which are made with ricotta) in that it is made with olive oil, grated hard cheese and clams. There is no ricotta, and of course no tomato sauce used.
New York Style
New York style pizza is made with mozzarella and tomato sauce. Anything else is considered a topping. The dough is one of the most unique aspects of the pizza. Some credit the high gluten content of the flour for the pizzas chewy texture, while others think that it's something in the water. One west coast celebrity even brought in NYC water in order to replicate the famous texture.
Unlike some styles that are not suitable for street food, such as Chicago style, NYC style pizza is very popular with people on the go. Walk into any NYC pizzeria and you will see people lined up buying single slices and walking out the door to eat them. The slices are large, and thin, and fold over easily. They are not messy to eat and are perfect for people who don't have time to sit down and eat.
Chicago style pizza is famous around the country for its deep-dish cooking method. As opposed to NYC and other styles, where the dough is spread out and then slid into an oven on a pizza board, Chicago style pizza dough is placed into a deep metal dish, similar to what a pie or cake might be cooked in. This is done because the pizza is much thicker and has more cheese and sauce than other styles. The metal dish prevents the dough from collapsing.
Because it is such a thick pizza it takes more time to cook than thin crust. For this reason the toppings are inverted. Cheese and any other toppings (meat, peppers, olives, etc…) are placed on the crust and then covered with sauce. This is done because the longer cooking time would cause the cheese to completely burn. The layer of sauce keeps the cheese and other ingredients from burning during the long cooking time.
Trenton style pizza is unique in that the tomato sauce is placed on top of the cheese. The pizza dough is covered with shredded mozzarella and then the crushed tomatoes are put on top. Unlike NYC style tomato sauce, which is thin and can be spread with a ladle spoon, the Trenton style tomato topping is think and chunky. It is baked in a very hot oven and you get a super crisp crust. The tomatoes on top are not stewed into a sweet, marina style sauce, but rather have the wonderful tartness of a plain, crushed tomato topping. The brilliance of the combination is the contrast of the savory cheese and the tangy tomato.
Keep these things in mind when ordering pizza delivery in New York.