Maillard Reaction vs. Caramelization on Pizza: What's Actually Browning

A pizza comes out of the oven brown in some places and pale in others, and the reasons are mostly about water and heat, then about sugar. This page explains the two browning reactions, when they can happen, where the sugar comes from, and what to change if your crust stays pale.

Two kinds of browning

Modernist Pizza (2021), by Nathan Myhrvold and Francisco Migoya, separates them simply. Caramelization is a reaction involving a single kind of compound: sugar, broken down by heat. When amino acids are present along with sugars, Maillard reactions happen “instead of or in addition to caramelization.” These are much more complex, involving proteins, peptides and amino acids reacting with a set of sugars “to create thousands of new flavor compounds.” The book’s comparison: “Caramelization is like a tuning fork, while Maillard reactions are like a symphony orchestra.”

Pizza dough always contains both sugar and protein, and Modernist Pizza describes the browning of the crust, and the flavor that comes with it, in terms of Maillard reactions.

Why a wet crust can’t brown

Modernist Pizza describes the crust browning in stages:

1. Heating while wet. Dough holds a lot of water. While its surface is wet, it can’t get much hotter than 212°F (100°C), because nearly all the incoming heat goes into turning water to steam.
2. Drying. Once the outer layer’s water has boiled off, the surface temperature climbs again.
3. Browning. Above roughly 265°F (130°C), Maillard reactions start to occur rapidly. The crust typically tops out at around 320 to 355°F (160 to 180°C).
4. Speeding up. As the crust darkens, it absorbs more of the oven’s radiant heat, so “the darker the pizza gets, the faster it darkens.”

That explains the pattern on a finished pizza. The book notes that a crust forms where the exterior dries out, wherever the dough isn’t covered by sauce, so the rim and the underside brown first. The middle, under wet sauce and cheese, stays near boiling for much longer; Modernist Pizza found the evaporating sauce draws so much heat that the dough below can’t dry out. It also explains why stray flour on the outside stays pale: the book notes that the enzymes that turn starch into browning sugars only work once flour is wet, so dry flour browns at much higher temperatures.

Where the sugar comes from

Most of the sugar that browns a crust is made in the dough. Once water is added, the flour’s enzymes, chiefly amylase, break starch, especially starch granules damaged in milling, into sugars; Modernist Pizza describes the supply as limited by the pace of the enzymes. Those sugars feed the yeast, and whatever the yeast doesn’t eat is left to brown the crust.

Several things change how much is left:

• A long fermentation can use it up. Modernist Pizza notes that during long fermentations the yeast consumes large amounts of simple sugars, and if nothing compensates, the crust may bake to a dull color. That’s why pizzaioli often add diastatic malt to long-fermented doughs.
• Salt matters. The book explains that salt slows fermentation, and that unsalted dough bakes into a relatively pale crust because the yeast have eaten the sugar that would have browned it. It says slowing fermentation, as salt and cold-proofing do, brings richer flavors and darker crusts.
• Malted flour adds enzymes. Modernist Pizza explains that malting sprouts grain so it produces more amylase, and that malted barley is sometimes added to wheat flour. King Arthur Baking notes that diastatic malt is commonly added to all-purpose and bread flours; look for malted barley flour, or an added enzyme, in the ingredient list. If your flour has no added malt or enzymes, a recipe may call for a small amount of diastatic malt; check your bag and the malt maker’s directions.
• Added sugar supplies it directly. Sugar, honey or malt syrup in a dough add sugar for browning, though not the enzymes that keep making it. Modernist Pizza adds malted barley syrup to one of its regional pizzas, its Quad Cities pizza, because it aids browning.

So fermentation cuts both ways. A cold, slow ferment leaves the flour’s enzymes time to free up sugar, but the yeast is eating sugar the whole time, and a dough fermented for a long time can come out paler, not darker.

Why kitchen ovens struggle

A pizza oven browns a Neapolitan-style pizza in a minute or two. The AVPN’s 2024 regulations call for 60 to 90 seconds on a floor of about 380 to 430°C (715 to 805°F) under a dome of about 485°C (905°F); the 2010 EU specification for Pizza Napoletana gives the same bake time but reverses the two temperatures, with the floor at about 485°C and the dome at about 430°C. A kitchen oven tops out around 500 to 550°F (260 to 288°C), and a pizza spends several times as long in it. With less heat arriving per second, especially from above, the crust may be cooked through before the surface has dried and browned. Pizza oven thermodynamics explains why the setting alone doesn’t tell you how fast heat reaches the pizza.

A pale crust: what to change, in order

1. The heat. Preheat a steel or stone fully at the oven’s hottest setting: the Pizza Planner allows 45 to 60 minutes, or longer where your steel’s maker says so. Bake on an upper rack and, if the top and rim stay pale, finish under the broiler as your oven’s manual allows. Bake until the underside is browned, not by the clock.
2. The dough and toppings. Go easier on wet sauce and toppings if the middle stays pale. Brush off excess flour before launching. If the dough was fermented long or went past its peak, the yeast may have used up its sugar.
3. The flour. Read the bag. If the ingredients include malted barley flour or an enzyme, adding malt shouldn’t be your first move. If the flour is unmalted, try a malted flour suited to your style in the next batch, changing nothing else, or a small dose of diastatic malt.

If you add diastatic malt, follow your product’s own label rather than a percentage from a recipe written for a different malt; products vary in strength. King Arthur’s label says “1/2 to 1 teaspoon per 3 cups of flour,” which comes to about 0.28 to 0.56% of the flour weight for that product, using the label’s 2 g per teaspoon and King Arthur’s 120 g per cup of bread flour (our calculation). King Arthur also warns that too much diastatic malt gives a gummy result. In a very hot pizza oven, heat alone browns the crust in a minute or two, and the traditional Neapolitan dough has no malt in it at all. The diastatic malt guide and pizza crust not browning go further.

Cheese and toppings

Toppings brown by the same rules: they have to dry before they color. Cheese adds a twist. Modernist Pizza observes that mozzarella, unlike most foods, gets whiter as it bakes, so it reflects more of the oven’s radiant heat and the heat going into it changes by a factor of two. Melting it also takes a lot of energy. If the cheese browns long before the crust does, see cheese burning before the crust cooks.

Sources

• Nathan Myhrvold and Francisco Migoya, Modernist Pizza (2021), volume 1, printed pages 274–275 (starch, damaged starch and flour enzymes), 281 (malted flour), 312 (salt, fermentation and crust color), 315 (sugar, caramelization and Maillard reactions, sugar depletion in long fermentations, malted barley syrup), 363–365 (how the crust dries and browns, wet-bulb temperature, raw flour), 369 (sauce slowing the dough beneath) and 372–373 (mozzarella’s reflectivity).
• European Commission, Regulation (EU) No 97/2010, Annex II: the Pizza Napoletana specification (ingredients, floor and dome temperatures, bake time). Checked October 14, 2026.
• Associazione Verace Pizza Napoletana: International Regulations, 2024 edition, printed page 12 (base and dome temperatures, cooking time). Checked October 14, 2026.
• King Arthur Baking: Diastatic Malt Powder product page and package label (usage directions; 1 teaspoon = 2 g), ingredient weight chart (bread flour), and Annabelle Shippee, “What’s the difference between diastatic and non-diastatic malt?” (2022), on malt in commercial flours and on overuse. Checked October 14, 2026.