It depends on the type of tortilla. Traditional corn tortillas are unleavened, made with just ground corn and water. Most flour tortillas, however, contain baking powder or sodium bicarbonate, making them technically leavened. This distinction matters for everyday cooking, religious observances, and understanding what’s actually in the tortillas you buy.
Corn Tortillas Are Unleavened
A traditional corn tortilla contains no leavening agent whatsoever. The process starts with dried corn kernels cooked in a 1% calcium hydroxide solution at about 80°C for an hour, then soaked in that same solution for 16 to 18 hours. This ancient technique, called nixtamalization, softens the kernels and makes their nutrients more available. After soaking, the corn is rinsed and ground into a dough called masa, with a water content around 55%.
That’s it: corn, water, and the alkaline solution used during processing. No yeast, no baking powder, no baking soda. The calcium hydroxide serves a chemical purpose (breaking down the outer hull of the kernel and changing the protein structure), but it does not produce gas or cause the dough to rise. Corn tortillas are flat because nothing in them creates air bubbles. They’re as unleavened as bread gets.
Flour Tortillas Usually Are Leavened
Flour tortillas are a different story. One of the most important components in a flour tortilla recipe is the leavening system. Most commercial flour tortillas use a chemical leavening process: sodium bicarbonate (baking soda) reacts with an acid ingredient to release carbon dioxide gas. Those gas bubbles get trapped in the dough during mixing, then expand when the tortilla hits the hot surface, giving flour tortillas their characteristic puffiness, opacity, and soft texture.
This is the same basic chemistry behind biscuits, pancakes, and quick breads. The leavening reaction’s timing matters a lot. If the gas releases too early during processing, the bubbles escape before baking and you end up with a pale, flat, translucent tortilla. Manufacturers carefully calibrate when and how fast the reaction happens. Commercial producers even use specially formulated sodium bicarbonate granulations designed specifically for tortilla production, targeting height, uniform cell structure, and what the industry calls a “bready texture.”
Research into commercial tortilla manufacturing has tested multiple acid ingredients paired with sodium bicarbonate, including sodium aluminum phosphate, monocalcium phosphate, and sodium acid pyrophosphate, all to optimize how flour tortillas rise. Some formulations add fumaric acid to improve storage stability and reduce the amount of other leavening chemicals needed. If you pick up a package of flour tortillas at the grocery store and read the ingredients, you’ll almost certainly find baking powder or sodium bicarbonate listed.
The Homemade Exception
Here’s where it gets nuanced. You can make flour tortillas at home with just three ingredients: flour, water, and fat (oil or lard). No baking powder, no baking soda. These homemade versions are genuinely unleavened and will be thinner, denser, and less puffy than store-bought flour tortillas. Some people make them this way specifically because they want unleavened bread.
So “flour tortilla” doesn’t automatically mean “leavened.” It depends on the recipe. But the vast majority of flour tortillas sold commercially are leavened, and most home recipes call for at least a small amount of baking powder.
What This Means for Passover and Religious Observances
Many people searching this question want to know whether tortillas qualify as unleavened bread for Passover or other religious observances that prohibit leavening. Corn tortillas made traditionally (masa and water) are unleavened by any definition. Homemade flour tortillas without baking powder also qualify.
However, Passover rules for Jewish observance go beyond just leavening agents. Chametz, the category of food forbidden during Passover, includes any wheat, barley, rye, oat, or spelt product that has been allowed to ferment or rise. Even a flour-and-water tortilla could be problematic if the dough sits too long before cooking. Many Ashkenazi Jewish traditions also avoid corn and other grains called kitniyot during Passover, which would rule out corn tortillas too. The specific rules vary by community and tradition, so the leavening question alone doesn’t settle whether a tortilla is Passover-appropriate.
For Christian observances of communion or the Feast of Unleavened Bread, simple corn tortillas or basic flour-water-fat tortillas are widely accepted as unleavened bread.
How to Tell What You’re Eating
If you’re buying tortillas at the store, check the ingredient list. Baking powder, sodium bicarbonate, and monocalcium phosphate are all leavening agents you’ll commonly see on flour tortilla packages. Corn tortilla packages typically list just masa flour (or corn, water, and lime) with no leavening agents.
If you’re making tortillas at home and want them unleavened, skip the baking powder. Your flour tortillas will be chewier and flatter, closer to a chapati or roti. Your corn tortillas won’t change at all, since they never had leavening to begin with.