Pizza is a dish of Italian origin, made with an oven-baked, flat, generally round bread that is often covered with tomatoes or a tomato-based sauce and mozzarella cheese. Other toppings are added according to region, culture, or personal preference. Originating as a part of Italian cuisine, the dish has become popular in many different parts of the world, particularly the United States, where numerous varieties have been developed, pizza restaurant chains have flourished, and pizza has become a home delivery item as well as being available as a frozen food ready to bake at home.
Today, pizza is a symbol of several cultures: Italians, particularly from Naples, are proud of authentic pizza made with local ingredients and following strict guidelines for preparation. In the United States, pizza has iconic status as a typical American food, quickly prepared and readily available, and enjoyed by people of all ages at social occasions as well as family meals. The different styles, from places such as New York City and Chicago, reflect the diversity of American culture. Countries throughout the world have adopted pizza as a favorite food, adding their own variations to make this dish their own.
Delicious and relatively nutritious, particularly when topped with fresh vegetables, pizza is an example of human creativity. Items available to the general public are combined to make something that satisfies people's needs. Its adaptability reflects the endless diversity of human life and culture, which then acts as a never-ending source of happiness.
Pizza consists of a flattened disk of bread dough topped with olive oil, tomatoes, and mozzarella cheese (and in its variations other toppings), baked quickly, sliced into segments, and served hot.
The bottom base of the pizza (called the “crust” in the United States and Canada) may vary widely according to style: thin as in hand-tossed pizza or Roman pizza, thick as in pan pizza or Chicago-style pizza. It is traditionally plain, but may also be seasoned with butter, garlic, or herbs, or stuffed with cheese.
In restaurants, pizza can be baked in an oven with stone bricks above the heat source, an electric deck oven, a conveyor belt oven or, in the case of more expensive restaurants, a wood- or coal-fired brick oven. On deck ovens, the pizza can be slid into the oven on a long paddle called a peel and baked directly on the hot bricks or baked on a screen (a round metal grate, typically aluminum). When making pizza at home, it can be baked on a pizza stone in a regular oven to imitate the effect of a brick oven. Another option is grilled pizza, in which the crust is baked directly on a barbecue grill. Greek pizza, like Chicago-style pizza, is baked in a pan rather than directly on the bricks of the pizza oven.
Pizza has a long and complex history, although pizza as we know it today originated in Italy, specifically in Naples.
Bread is one of the oldest prepared foods and dates back at least to the neolithic. Records of people adding other ingredients to bread in order to make it more flavorful can be found throughout ancient history. The Ancient Greeks, for example, had a flat bread called plakous, which was flavored with various toppings like herbs, onion, and garlic. It is also said that soldiers of the Persian King, Darius the Great (521-486 B.C.E.) baked a kind of bread flat upon their shields and then covered it with cheese and dates, and in the first century B.C.E., Virgil refers to the ancient idea of bread as an edible plate or trencher for other foods in this extract from the Aeneid:
- Their homely fare dispatch’d, the hungry band
- Invade their trenchers next, and soon devour,
- To mend the scanty meal, their cakes of flour.
- Ascanius this observ’d, and smiling said:
- “See, we devour the plates on which we fed.”
These flatbreads, like pizza, were from the Mediterranean area and other examples of flat breads that survive to this day from the ancient Mediterranean world are "focaccia," which may date back as far as the Ancient Etruscans; "coca," which has sweet and savory varieties from Catalonia and the Balearic Islands; and the Greek "Pita" or "Pide" in Turkish. Similar flat breads in other parts of the world include the Indian "Paratha" , the South Asian "Naan," and the German "Flammkuchen."
The first recorded use of the word "pizza" dates from 997 C.E. This comes from a Latin text from the town of Gaeta in Southern Italy, stating that a tenant of certain property was to give the bishop of Gaeta duodecim pizze, "twelve pizzas," every Christmas day, and another twelve every Easter Sunday..
The origin of the word pizza has been suggested to be Germanic, related to the English word "to bite." Italy was subject to domination by two Germanic-speaking peoples, the Goths and the Lombards (Langobards). Pizza could derive from a Lombardic word similar in form to the Old High German bizzo or pizzo, related to words meaning "bite." This word originally meant "mouthful" (what one obtains by "biting"), then later "piece of bread" (the typical content of a mouthful).
The innovation that gave us the particular flat bread we call “pizza” was the use of tomato as a topping. Brought to Europe from the Americas in the sixteenth century, the poor of the area around Naples began to add tomato to their yeast-based flat bread, and so the pizza was born. The dish gained in popularity, and soon pizza became an attraction to visitors who ventured into the poorer areas of the city in order to try the local specialty.
Until about 1830, pizza was sold from open-air stands and street vendors out of pizza bakeries, a tradition that is still kept alive today by some pizzerie. Antica Pizzeria Port’Alba in Naples is widely regarded as the world's first pizzeria. They started producing pizzas for peddlers in 1738, but expanded to a pizza restaurant with chairs and tables in 1830, and still serve pizza from the same premises today.
A description of pizza in Naples around 1830 is given by the French writer Alexandre Dumas, père in his work Le Corricolo, in which he wrote that pizza was the only food of the humble people in Naples during winter, and that "in Naples pizza is flavored with oil, lard, tallow, cheese, tomato, or anchovies."
Purists, like the famous pizzeria Da Michele (founded 1870) consider there to be only two true pizzas—the “Marinara” and the “Margherita”—and that is all they serve. The marinara is the oldest and has a topping of tomato, oregano, garlic, extra virgin olive oil, and usually basil. It was named marinara not, as many believe, because it has seafood on it (which it does not), but because it was the food the fishermen ate when they returned home from fishing trips in the Bay of Naples. The Margherita is attributed to baker Raffaele Esposito. In 1889, he baked three different pizzas for the visit of King Umberto I and Queen Margherita of Savoy. The Queen's favorite was a pizza evoking the colors of the Italian flag—green (basil leaves), white (mozzarella), and red (tomatoes). This combination was named Pizza Margherita in her honor.
Today, there are many famous pizzerias in Naples where these traditional pizzas can be found; most of them are located in the ancient historical center of Naples.
Pizza first made its appearance in the United States with the arrival of Italian immigrants in the late-nineteenth century. In cities with large Italian populations, such as San Francisco, Chicago, New York City, and Philadelphia pizza was first sold on the streets of Italian neighborhoods.
The first "official" pizzeria is generally believed to have been founded by Gennaro Lombardi in Little Italy in New York. Gennaro Lombardi opened a grocery store in 1897 which later was established as the first pizzeria in America in 1905 with New York's issuance of the mercantile license. An employee of his, Antonio Totonno Pero, began making pizza for the store to sell that same year. The price for an entire pizza was five cents, but since many people could not afford the cost of a whole pie, they could instead say how much they could pay and they were given a slice corresponding to the amount offered. In 1924, Totonno left Lombardi's to open his own pizzeria on Coney Island called Totonno's. While the original Lombardi's closed its doors in 1984, it was reopened in 1994 just down the street and is run by Lombardi's grandson.
Pizza was brought to the Trenton area of New Jersey with Joe's Tomato Pies opening in 1910, followed soon by Papa's Tomato Pies in 1912. In 1936, Delorenzo's Tomato Pies was opened. While Joe's Tomato Pies has since closed, both Papa's and Delorenzo's have been run by the same families since their openings and remain popular in the area. Frank Pepe Pizzeria Napoletana in New Haven, Connecticut, was another early pizzeria which opened in 1925 (after the owner served pies from local carts and bakeries for 20 to 25 years), and is famous for its New Haven-style clam pie. Frank Pepe's nephew Sal Consiglio opened a competing store, Sally's, on the other end of the block, in 1938. Both establishments are still run by descendants of the original family. The D'Amore family introduced pizza to Los Angeles in 1939.
Prior to the 1940s, pizza consumption was limited mostly to Italian immigrants and their descendants. The international breakthrough came after World War II. Allied troops occupying Italy, weary of their rations, were constantly on the lookout for good food. They discovered the pizzeria, and local bakers were hard-pressed to satisfy the demand from the soldiers. The American troops involved in the Italian campaign took their appreciation for the dish back home, touted by "veterans ranging from the lowliest private to Dwight D. Eisenhower."
The modern pizza industry, popular throughout the United States and with it uniquely American character, was born in the Midwestern United States. Ric Riccardo pioneered what became known as the deep dish pizza when, in 1943, he and Ike Sewell opened Pizzeria Uno in Chicago, and a generation later, Tom Monaghan launched what soon became known as Domino's Pizza, credited by some for popularizing free home delivery.
With its rising popularity, chain restaurants moved in. Today, the American pizza business is dominated by companies that specialize in pizza delivery.
Some pizzas can be very high in salt and fat and concerns have been raised about the negative effect these pizzas can have on people’s health. For example, Pizza Hut has come under criticism for the high salt content of some of their meals, which were found to contain more than twice the daily recommended amount of salt for an adult.
However, it should also be noted that commercially made fast-food pizza is very different from well-made Italian pizza, particularly from a good restaurant which is concerned with using only good ingredients, or even more so in a homemade pizza. The salt and saturated fat content of a homemade pizza is usually far less if using original recipes. Mozzarella cheese is less fatty than many other cheeses. Feta cheese, which has an even lower saturated-fat content, is often used in homemade-pizza recipes. There is also the possibility of including other healthy ingredients in the toppings, such as fresh tomatoes, bell peppers, mushrooms, spinach, zucchini, eggplant, and so forth.
Italian, and in particular Neapolitans, take their pizza very seriously. A bill was brought before Parliament to safeguard the "traditional Italian pizza," specifying permissible ingredients and methods of processing. Only pizzas which followed these guidelines could be called “traditional Italian pizzas,” at least in Italy.
Italy has also requested that the European Union safeguard some traditional Italian pizzas, such as “Margherita” and “Marinara”. The European Union enacted a protected designation of origin system in the 1990s.
The pizza bases in Naples are soft and pliable, but in Rome they prefer a thin and crispy base. Another popular form of pizza in Italy is "pizza al taglio," which is pizza baked in rectangular trays with a wide variety of toppings and sold by weight.
Neapolitan pizza (pizza napoletana)
Authentic Neapolitan pizzas are made with local ingredients such as San Marzano tomatoes, which grow on the volcanic plains to the south of Mount Vesuvius, and Mozzarella di Bufala Campana, made with the milk from water buffalo raised in the marshlands of Campania and Lazio in a semi-wild state (this mozzarella is protected with its own European protected designation of origin). Genuine Neapolitan pizza dough consists of Italian wheat flour (type 0 or 00, or a mixture of both), natural Neapolitan yeast or brewer’s yeast, salt, and water.
For proper results, strong flour with high protein content (as used for bread-making rather than cakes) must be used. The dough must be kneaded by hand or with a low-speed mixer. After the rising process, the dough must be formed by hand without the help of a rolling pin or other mechanical device, and may be no more than 3 millimeters (0.12 in) thick. The pizza must be baked for 60 to 90 seconds in a 485 °C (905 °F) stone oven with an oak-wood fire. When cooked, it should be crispy, tender, and fragrant. Neapolitan pizza has been given the status of a “guaranteed traditional specialty” in Italy. This allows only three official variants: pizza marinara, which is made with tomato, garlic, oregano, and extra-virgin olive oil (although most Neapolitan pizzerias also add basil to the marinara); Margherita, made with tomato, sliced mozzarella, basil, and extra-virgin olive oil; and pizza Margherita extra, made with tomato, buffalo mozzarella from Campania in fillets, basil, and extra-virgin olive oil.
Lazio style (Roman)
- Take-away shops sell pizza rustica or pizza al taglio. This pizza is cooked in long, rectangular baking pans and relatively thick (one to two centimeters). The crust is similar to that of an English muffin, and the pizza is often cooked in an electric oven. It is usually cut with scissors or a knife and sold by weight.
- In pizza restaurants (pizzerias), pizza is served in a dish in its traditional round shape. It has a thin, crisp base quite different to the thicker and softer Neapolitan style base. It is usually cooked in a wood-fired oven, giving the pizza its unique flavor and texture. In Rome, a pizza napoletana is topped with tomato, mozzarella, anchovies, and oil. Thus, what in Naples is called pizza romana, in Rome is called pizza napoletana.
Other types of Lazio-style pizza include:
- Pizza romana (in Naples): tomato, mozzarella, anchovies, oregano, oil;
- Pizza viennese: tomato, mozzarella, German sausage, oregano, oil;
- Pizza capricciosa (“capricious pizza”): mozzarella, tomato, mushrooms, artichokes, cooked ham, olives, oil (in Rome, prosciutto raw ham is used and half a hard-boiled egg is added);
- Pizza quattro stagioni (“four seasons pizza”): same ingredients for the capricciosa, but ingredients not mixed;
- Pizza quattro formaggi (“four cheese pizza”): tomatoes, mozzarella, stracchino, fontina, gorgonzola (sometimes ricotta can be swapped for one of the last three);
- Sicilian-style pizza has its toppings baked directly into the crust. An authentic recipe uses neither cheese nor anchovies. “Sicilian” pizza in the United States is typically a different variety of product made with a thick crust characterized by a rectangular shape and topped with tomato sauce and cheese (and optional toppings). Pizza Hut’s “Sicilian Pizza,” introduced in 1994, is not an authentic example of the style as only garlic, basil, and oregano are mixed into the crust;
- White pizza (pizza bianca) uses no tomato sauce, often substituting pesto or dairy products such as sour cream. In Rome, the term pizza bianca refers to a type of bread topped with olive oil, salt and, occasionally, rosemary leaves. It is also a Roman style to top the white pizza with figs, the result called pizza e fichi (pizza with figs);
- Ripieno or calzone is a pizza in the form of a half moon, sometimes filled with ricotta, salami, and mozzarella; it can be either fried or oven baked.
Non-Italian types of pizza
In the twentieth century, pizza became an international food, with the toppings varying considerably in accordance with local tastes. These pizzas consist of the same basic design but include an exceptionally diverse choice of ingredients.
Due to the influence of Italian and Greek immigrants in American culture, the United States has developed a large number of regional forms of pizza, many bearing only a casual resemblance to the Italian original. During the latter half of the twentieth century, pizza in the United States became an iconic dish of considerable popularity. Often, "Americanized" foods such as barbecued chicken and bacon cheeseburgers are used to create new types of pizza. Mexican pizza, or taco pizza, is also popular.
American pizza often has vegetable oil or shortening (often, but not always, olive oil) mixed into the dough; this is not as common in Italian recipes. This can range from a small amount in relatively lean doughs, such as New York style, to a very large amount in some recipes for Chicago-style deep-dish dough. In addition, American pizza (at least thin-crust) is often made with a very high-gluten flour (often 13 to 14-percent protein content) of the type also used to make bagels; this type of flour allows the dough to be stretched rather thinly without tearing, similar to strudel or phyllo dough.
Various toppings may be added, most typically:
- Tomato sauce usually replaces the tomato mixture used on Italian-style pizzas, and is usually a fairly heavily seasoned, smooth sauce with a low water content. On some variants without tomatoes, pesto, alfredo, and barbecue sauce are also used.
- Cheese, usually mozzarella but also provolone, cheddar, parmesan, or a blend of other cheeses.
- Fruits and vegetables such as garlic, artichoke hearts, eggplant, olives, capers, onions, spinach, tomatoes, bell peppers, green chili peppers, jalapeños, banana peppers, and pineapple.
- Fungi, usually mushrooms and rarely truffles.
- Meat, such as sausage, (pepperoni, salami, or Italian sausage), ham, bacon, ground beef, and chicken.
- Seafood such as anchovies, tuna, salmon, and shrimp.
- Herbs and spices such as basil, oregano, and black pepper.
- Nuts such as cashews, pistachios, and pine nuts.
- Oils such as olive oil, walnut oil, and truffle oil.
In some pizza recipes the tomato sauce is omitted (termed “white pizza”), or replaced with another sauce (usually garlic butter, but sauces can also be made with spinach or onions).
Numerous variations exist across the United States. These can be bought in restaurants and pizzerias, or baked at home. Following are some of the more well-known styles:
- New York
New York-style pizza is a style originally developed in New York City by immigrants from Naples. It is often sold in generously sized, thin, and flexible slices. It is traditionally hand-tossed, moderate on sauce, and moderately covered with cheese essentially amounting to a much larger version of the Neapolitan style. The slices are sometimes eaten folded in half, or even stacked, as its size and flexibility may otherwise make it unwieldy to eat by hand. This style of pizza dominates in the Northeastern states, and is very similar to the basic style common through the United States known simply as "pizza." Many pizza establishments in the New York metropolitan area offer two varieties of pizza: “Neapolitan,” or “regular,” made with a relatively thin, circular crust, and served in wedge-shaped slices, and “Sicilian,” or “square,” made with a thicker, rectangular crust, and served in large, rectangular slices.
- New Haven
New Haven-style pizza is popular in southern Connecticut. It has a thin crust that varies between chewy and tender, depending on the particular establishment. The default version is a “white” pizza topped with only garlic and hard cheeses; customers who want tomato sauce or mozzarella cheese have to ask for them explicitly. A pizza has a very dark, “scorched” crisp crust that offers a distinctive bitter flavor, which can be offset by the sweetness of tomatoes or other toppings.
- Greek pizza
Greek pizza is a variation popular in New England. Its name comes from the style of pizzerias owned by Greek immigrants. It has a thicker, chewier crust and is baked in a pan in the pizza oven, instead of directly on the bricks. Plain olive oil is a common part of the topping, as well as being liberally used to grease the pans and crisp the crust. Variations in other parts of the country include using feta cheese, Kalamata olives, and Greek herbs such as oregano.
Chicago-style pizza, or deep-dish pizza, contains a crust which is formed up the sides of a deep-dish pan. It reverses the order of some ingredients, using crust, cheese, filling, then sauce on top. Some versions (usually referred to as "stuffed") have two layers of crust with the sauce on top.
Chicago-style thin-crust pizza has a thinner crust than Chicago-style deep dish, and is baked flat rather than in a deep-dish pan. The crust is thin and firm enough to have a noticeable crunch, unlike a New York-style pizza, yet thick enough to be soft and doughy on the top. The crust is invariably topped with a liberal quantity of southern-Italian style tomato sauce, which is usually quite herbal or highly spiced, and typically contains no visible chunks of tomato. Next, a layer of toppings is added, and a layer of mozzarella cheese which frequently separates from the bottom crust due to the quantity of tomato sauce. Chicago-style thin-crust pizzas are cut into three-to-four-inch squares, also known as “party cut,” as opposed to a “pie cut” into wedges. The small size of the squares makes it unnecessary to fold the slices. Chicago-style pizza is prevalent throughout the Midwestern United States.
- St. Louis
St. Louis-style pizza is a thin crust variant that is popular in and around St. Louis, Missouri. The most notable characteristic of St. Louis-style pizza is the distinctively St. Louisan Provel cheese used instead of (or rarely in addition to) mozzarella cheese. The toppings usually consist of fresh ingredients, sliced instead of diced. It is common for the pizza to be topped with large pieces of onion, round slices of bell pepper, and full strips of bacon. The crust is thin enough that it becomes very crunchy in the oven and is sometimes compared to a cracker. Even though the crust is round, it is always cut into small squares.
California-style pizza refers to pizza with non-traditional ingredients, especially those that use a considerable amount of fresh produce. A Thai-inspired chicken pizza with peanut sauce, bean sprouts, and shaved carrots is a popular variant in California-style pizza restaurants, as are pizzas that use chicken and barbecue sauce as toppings.
Hawaiian pizza has Canadian bacon (or sliced ham) and pineapple toppings with mozzarella cheese. This type of pizza is especially popular in the western United States, and is also a popular topping combination in Australia, Canada, and Sweden, but notably not in Hawaii. This type is also common within the EU, where it is known as "pizza Hawaii."
Grilled pizza, invented in Providence, Rhode Island, uses a fairly thin crust cooked on a grill; the toppings are placed on the baked side after the pizza has cooked a while and flipped over.
English muffin, French bread pizza, and pizza bagels are common convenience pizzas made at home in an oven or toaster, usually with a simple topping of tomato sauce, sliced or shredded cheese, and perhaps pepperoni. French bread pizza is sometimes available commercially as a frozen meal.
- Frozen and ready-to-bake pizzas
Pizza is also found as a frozen food in grocery stores and supermarkets. A considerable amount of food-technology ingenuity has gone into the creation of palatable frozen pizza. The main challenges include preventing the sauce from combining with the dough and producing a crust that can be frozen and reheated without becoming rigid. Modified corn starch is commonly used as a moisture barrier between the sauce and crust. Traditionally, the dough is somewhat pre-baked and other ingredients are also sometimes pre-cooked. More recently, frozen pizzas with completely raw ingredients have also begun to appear, as have those with “self-rising” crusts. Many grocery stores and supermarkets also sell fresh, ready-to-bake pizzas.
Pizza is popular in Australia, where a significant percentage of the population is of Italian descent. The usual Italian varieties are available, but there is also the "Australian," or "australiana," which has the usual tomato-sauce base and mozzarella cheese with bacon and egg (seen as quintessentially Australian breakfast fare). Prawns are also sometimes used on this style of pizza.
In the 1980s, Australian pizza shops and restaurants began selling "gourmet pizzas," essentially pizzas with upmarket ingredients such as salmon, dill, bocconcini, tiger prawns, and even such toppings as kangaroo, emu, and crocodile meats. Wood-fired pizzas, cooked in an impressive-looking ceramic oven heated by wood fuel, are also popular.
Pizza is a very popular dish in Brazil, brought by Italian immigrants to that country. Sao Paulo, a city that calls itself 'The Pizza Capital of the World', hosting more than 6,000 pizza establishments and where more than 1.4 million pizzas are consumed every day.. Typically, pizzas follow the Neapolitan variety, rather than the Roman one, being thicker and more doughy.
Pizza has emerged as a popular fast food in Indian urban areas, particularly among youth. Pizza outlets serve pizzas with several Indian-based toppings, such as Tandoori chicken and cottage cheese (Known as Paneer in India). Indian pizzas are generally more spicy compared to their Western counterparts, in order to suit Indian taste. Along with Indian variations, more conventional pizzas are also available.
- Martin Maiden, Pizza is a German(ic) Word! Linguistic Wonder Series, YourDictionary.com, 2008. Retrieved January 23, 2009.
- Antica Pizzeria Port'Alba Association Verace Pizza Napoletana. Retrieved January 25, 2009.
- Alexandre Dumas, Chapitre VIII - Le lazzarone, Biblioteque Dumas.
- Antica Pizzeria "Da Michele" dal 1870, La Storia Retrieved February 6, 2009.
- Pizza History Museum, Queen Margherita Retrieved February 6, 2009.
- Hanna Miller, American Pie, American Heritage Magazine 57(2) (April/May 2006). Retrieved February 6, 2009.
- Fast food salt levels 'shocking' BBC NEWS, October 18, 2007. Retrieved February 6, 2009.
- Senato della Repubblica, Permissible ingredients and methods of processing Atto Senato n. 5016. Retrieved February 6, 2009.
- Senato della Repubblica, Bill for traditional Italian pizza Disegno di legge N. 5016. Retrieved February 6, 2009.
- Claudia Fortini, Più vicina la tutela europea per la pizza, Agricoltura Italiana Online, 2008. Retrieved February 6, 2009.
- Associazione vera pizza napoletana, Rules of the VPN Association. Retrieved February 7, 2009.
- Diane Morgan and Tony Gemignani, Pizza: More than 60 Recipes for Delicious Homemade Pizza (Chronicle Books, 2005, ISBN 0811845540).
- Gazeta Mercantil, Capital da pizza, sabores para todos Gazeta Mercantil (Brasil), 10/07/2007. Retrieved February 7, 2009.
ReferencesISBN links support NWE through referral fees
- Karmel, Elizabeth, and Bob Blumer. Pizza on the Grill: 100 Feisty Fire-roasted Recipes for Pizza & More. Newtown, CT: Taunton Press, 2008. ISBN 9781600850066
- Katz, Solomon H., and William Woys Weaver. Encyclopedia of Food and Culture. New York, NY: Scribner, 2003. ISBN 9780684805689
- McNair, James. Pizza. San Francisco, CA: Chronicle Books, 1987. ISBN 9780877014812
- Morgan, Diane, and Tony Gemignani, Pizza: More than 60 Recipes for Delicious Homemade Pizza. Chronicle Books, 2005. ISBN 0811845540
- Puck, Wolfgang, and Steven Rothfeld. Wolfgang Puck's Pizza, Pasta and More! New York, NY: Random House, 2000. ISBN 9780679438878
- Stucchi, Lorenza De' Medici, and Chuck Williams. Pizza. Alexandria, VA: Time-Life Books, 1993. ISBN 9780783502298
All links retrieved November 24, 2022.
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