According to the Iowa Corn Growers Association, the sweet corn we eat on the cob during the summer makes up just 1 percent of the corn grown in the United States. Much of the other 99 percent of corn grown is field corn, the variety used to make corn tortillas. When harvested, field corn kernels, which are high in starch and low in sugar, are dry and hard. To ready field corn for use in corn tortillas, it goes through a chemical process called nixtamalization. The corn is soaked for a number of hours in an alkaline solution, usually food-grade pickling lime (also known as slaked lime or food-grade calcium hydroxide), which softens and breaks down the shells surrounding the kernels. This soaking also boosts the corn’s nutritional value, brightens its color, and develops its buttery, earthy “corn chip” flavor. The kernels are then drained, rinsed, and milled into masa, which can be rolled immediately into tortillas or dried further into masa harina (a form of flour). Traditional homemade corn tortillas are rolled by hand or formed using a tortilla press and cooked on a comal, a flat cast-iron griddle.

The process of making large volumes of supermarket tortillas differs from making homemade tortillas in a few key ways. Most commercial manufacturers add gums and preservatives to prolong the shelf life of their tortillas and also incorporate other additives to improve their texture and flexibility. Some companies add gluten, the protein that gives wheat doughs elasticity, which makes their tortillas softer and more pliable. The gluten can come from wheat flour and/or wheat gluten, which is made by removing the starches from flour. To form the tortillas, some doughs are portioned into balls and heat-pressed, or, more commonly, the dough is passed through a sheeter before being die-cut—a sharp metal die, similar to a cookie cutter, creates multiple uniform shapes at once. No matter how they are formed, the tortillas are cooked and cooled before packaging. 

Our ideal corn tortilla has corn-forward flavor, mild sweetness, and a slight nuttiness developed from nixtamalization. A few of the tortillas we tasted hit all those notes, exhibiting “slightly sweet,” “pleasant corn flavor.” In the pork taco tasting, tasters noted that the mild corn flavor of those tortillas “complemented” the pork and “let the flavor of the filling shine through.” In comparison, other samples tasted “bland” and had “very little corn flavor.” One tortilla tasted slightly “musty.”

Since most commercial corn tortillas are produced from the same high-yield commodity corn, we wondered why some of the tortillas had more corn flavor than others. During our research, we learned that several factors influence flavor: the length of the nixtamalization period, how the masa is processed, and how the tortillas are cooked. Another factor is the amount of sugar and sodium in each tortilla. Higher-rated tortillas contained sugar (which occurs naturally in corn) and/or sodium. The lowest-ranked “musty” tortilla was the only product in our lineup that didn’t contain either.

Many factors also influence a tortilla’s texture: the amount of moisture left in the corn’s pericarp (outer layer) after nixtamalization, whether a company uses fresh masa or masa harina, and, if using masa harina, how it is rehydrated. Other important aspects include how the dough is flattened, cut, and cooked. Companies were reluctant to share details about their manufacturing processes, so we examined the nutrition information on the labels and measured the tortillas. 

The ingredient lists revealed that all but one tortilla contained preservatives. Those that did were pliable and tender, and tasters could wrap them easily around ingredients without ripping them. The one tortilla that didn’t contain preservatives was described as being “dry” and “stale” and was more delicate. We also noticed that the two tortillas that contained gluten, either from the addition of wheat flour or a combination of wheat flour and wheat gluten, were sturdy yet flexible and tender. In other words, they were less likely to rip and tear when rolled than traditional all-corn tortillas.

When we measured the thickness of all the tortillas, we discovered two things: Most of the all-corn tortillas were thinner than those that contained gluten, and our favorite all-corn tortilla was the thinnest in the lineup.

We had two favorites, and they were really different. Here's why:

Although we can recommend most of the tortillas we evaluated, two stood out. Tasters loved Guerrero White Corn Tortillas. These all-corn tortillas had “sweet corn flavor” and a “delicate but not dry” texture that made it easy to fold them around taco filling. Tasters also loved Maria and Ricardo’s Soft Yellow Corn Tortillas, which contain wheat flour and added gluten, noting their “subtle corn flavor” and describing them as “sturdy but not too doughy.” 

Because one of our top two tortillas contained gluten and one didn’t, we compared them in two core applications, Tex-Mex Cheese Enchiladas and tostadas. Both were easy to work with and tasted great, though we did notice differences. In the enchiladas, the thinner, smaller all-corn tortillas were especially delicate and light. Enchiladas made with the corn/wheat tortillas, on the other hand, were chewier. In the tostadas, the corn tortillas were crispier and had a delicate snap, while the corn/wheat tortillas were a bit doughy. We recommend using Guerrero White Corn Tortillas when frying. In every other application, either winner will serve you well.