Why is pizza so addicting? Although just a simple combination of dough, sauce, and toppings, pizza is now one of the most popular foods everywhere. Learn the science behind how the basic ingredients in pizza come together to create harmonious flavors in your mouth!
Background
Pizza goes way back to the time of the ancient Romans and are now a staple of freezers, takeout menus, and restaurants around the world. From simple flatbreads with toppings, this delicious ensemble of ingredients has evolved into many regional variations across the United States and in different countries.
I love trying various kinds of pizza with unique topping combinations and flavors on both thin and crispy crusts, as well as thick and chewy garlic-infused dough (very reminiscent of garlic bread). As I inhaled a slice of classic cheese pizza and chewed thoughtfully on the best part (the crust, of course), I wondered how this simple combination of dough, tomato sauce, and cheese could create such a delicious meal. I tried making my own pizza from scratch (as a much healthier alternative) to see if I could replicate such flavors with healthy ingredients. Researching the science behind these basic pizza components could let me recreate the most flavorful combinations each time!
Procedure
Pizza can often be made from pre-made dough (like the image of the flatbread pizza I made above), but this time I decided to start from scratch. I used shredded mozzarella cheese, spinach, sauteed mushrooms, and Canadian bacon for my toppings, but my scientific investigations will look at more traditional ingredients. For my specific recipe with servings and measurements click here.
For the dough, I saved a lot of time by using a bread machine, but it's the same process by hand. The machine whisked warm water, yeast, granulated sugar, olive oil, salt, and flour together before kneading the dough. I let the dough rise for about 2 hours in the machine. If I had let it rise for longer, perhaps 24 hours, the slow fermentation would have created more complex flavors (but I was hungry :)).
I let my Dutch oven heat up (just like my bread recipe) as I rolled the dough with a rolling pin into a disc. I prepared my toppings by sauteing the mushrooms in some olive oil, pepper, and salt and cutting up the Canadian bacon into smaller chunks. I then brushed the top of my pizza with some olive oil to prevent the filling from making the pizza crust soggy. I topped layers of cheese, spinach, mushrooms, and Canadian bacon (with some extra cheese on top!) and placed the pizza on parchment paper in the hot Dutch oven. The pizza was a big big, so the edges creased up nicely for the crust. I baked for about 15 minutes until the crust browned.
The dough was especially delicious - the hot Dutch oven had made the bottom crunchy and brown, but the sides were still chewy with a hint of olive oil flavor. The various toppings blended nicely, especially the wonderful aromas from the mushrooms, but I wondered if it would have tasted better with sauce (which sadly, I did not have at the time). Let's see if sauce is the key to flavorful pizza with science!
Science!
According to the American Chemical Society (ACS), pizza’s pleasing taste comes from properties in its basic ingredients and the chemical reaction that occurs in baking the pizza. Let's look at each of these ingredients - dough, tomato sauce, and cheese - and how they interact in the baking process!
We start with dough, which is usually a mixture of flour, salt, yeast and warm water. Olive oil and sugar can be added for flavor, as I did in my recipe. When these four basic ingredients are mixed together, the warm water causes the yeast to start breaking down the starches and complex sugars in the flour. This process produces ethanol and carbon dioxide, of which the latter is necessary for the dough to rise. Additionally, letting the dough rise for longer in a cool area, such as the refrigerator, allows the yeast to work longer and cause more fermentation. This creates secondary flavor molecules that greatly enhance the pizza's taste and counterbalance the yeast’s earthiness.
Furthermore, kneading dough creates gluten bonds in the flour that helps to trap the carbon dioxide and air bubbles for leavening while baking. This gluten network creates that chewy texture found in thicker crusts from longer kneading and stronger gluten bonds. However, this strong dough can also be rolled very thin without breaking, perfect for those crispy thin crusts. More on dough chemistry in my post on the science of bread-making here.
Next we have tomato sauce, an addition to virtually all pizzas - unless you happen to not have it in your pantry. Tomato sauce adds a bright flavor to a pizza, which is caused by the acidity in the tomatoes. However, if the pizza seems to sour or acidic, adding a tiny pinch of baking soda to the sauce can help by neutralizing some of that acid. Additionally, the way the moist sauce contrasts with drier dough makes it so appealing (like dipping bread into a sauce).
Finally, we have cheese, which ties it all together. That ooey-gooey, stringy deliciousness after it has melted on the pizza has a lot to do with how cheese is made in the first place. For one, most protein-based foods change texture when they are cooked, such as eggs that go from a liquid state to a relatively solid one. Thus, when milk is cooked to make cheese, it stays as a liquid but turns to a solid when acid is added. This acid is usually lactic acid, which helps the proteins in milk clump together and form curd. Mozzarella is the most commonly used cheese for pizza because it becomes so stretchy and gooey after it melts. This texture is due to the calcium ions added during the cheese-making process, which strengthens the protein molecules and makes the milk coagulate easier by further lowering the pH.
We've talked about texture, which certainly impacts taste, but how do these three ingredients come together to create such amazing flavor? Well, first let's discuss umami - a flavor meaning "delicious" in Japanese that is rich and savory.
Glutamate is an amino acid found in all protein foods and stimulates our umami taste perception. This enhance flavor, causing people to eat and crave such a food more. One example many people are familiar with is monosodium glutamate (MSG), which has great flavor-enhancing abilities and is often used in many dishes. Why is this important for pizza, which doesn't have any meat? Well, tomatoes and cheese, two of our fundamental pizza ingredients, are packed with lots of glutamate! This makes pizza so flavorful despite how simple it is. When we first bite that warm, soft crust topped with tomato sauce and cheese, our taste buds are stimulated by glutamate, so we want even more. It's love at first bite! Mushrooms also have glutamate, enhancing the flavor, which is why my pizza was still very aromatic despite not having tomato sauce.
Moreover, foods with similar flavor compounds are often thought to pair well together. Tomatoes and mozzarella cheese both contain 4-methylpentanoic acid, a flavor compound that makes these two ingredients a perfect pair. For the dough flavors, the carbohydrates of the dough are macronutrients that the brain likes, which causes you to keep wanting more slices as you eat that last bit of crust. This is actually also the case for cheese, which is packed with casein, a protein that releases casomorphins once digested. This, in turn, stimulates the morphine and k-opioid receptors in our brain which regular sensations of pleasure. Basically, eating melted cheese on a slice of pizza makes us extremely happy and satisfied. Pizza is a bomb of flavors ready to explode as soon as we eat it, so we crave those third or fourth slices!
Finally, when the pizza is cooked, the amazing Maillard reaction takes place, which creates the delicious savory flavors found in meats and bread. Put simply, the sugar and amino acids from protein molecules will react to create different flavor compounds and that brown crust above 140˚C. These additional flavors from the dough, along with the umami flavors already present in the sauce and cheese just goes to show why pizza is so addicting.
Conclusion
It's incredibly eye-opening to discover all the hidden molecules and chemistry that gives pizza such delicious flavors that keep people wanting more! Now I know that to get perfect flavor combinations, I need to first let the dough rise longer for more complex flavors, as well as knead it for those strong gluten bonds and perfect crust texture. It's also important to use ingredients with high glutamate content for that umami flavor, whether that's cheese, tomato sauce, mushrooms, or meat (perhaps not too many so I don't have the urge to finish the whole pizza in one sitting!). Lots and lots of cheese is definitely necessary though. Finally, it might be a good idea to look into certain food pairings so all my flavors blend cohesively. Next time you have time, skip buying greasy pizza from your local fast food chain and bake your own delicious pizza! You can even mix-and-match the toppings to get your perfect flavor combination.
Link to my homemade pizza recipe (from scratch).
Link to my post on the history & culture of pizza.
Want to Learn More? (always cite your sources, kids)
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