It is impossible to overstate the importance of tortillas to Mexican culture. Corn tortillas, made from nixtamalized corn, are the reason the Aztec empire thrived despite not having access to much in the way of animal protein. And even though Spanish conquistadors forced the native population to embrace wheat and bread, tortillas remain a staple in Mexican kitchens throughout the world.
Though packaged tortillas can be found at every grocery store in Mexico, locals maintain a relationship with their local tortilleria, a shop that specializes in making tortillas, and pick up a five or 10 peso sack of fresh tortillas every day before heading home for dinner. But how does the average person tell the difference between a good tortilla and a great one? For this we went to Mexico City local Ubish Yaren, a private chef and tour guide with Eat Mexico, who visits tortillerias on a regular basis.
According to Yaren, most tortillerias in Mexico City and in the U.S. don't make their own masa, or the dough used to make corn tortillas. They buy it from masa makers they trust, usually located on the outskirts of the city. Masa must be made fresh, daily, because the dough has a tendency to ferment quickly. A little bit of fermentation is fine, but too much can create off flavors in the finished tortillas.
"The best masa is not too yellow or too white, and moist, malleable," says Yaren. The color also changes depending upon what it will be used for: Street vendors often want masa that is more yellow if they're making flautas or quesadillas because, Yaren explains, "when you deep fry them it becomes a beautiful golden color," but if you are making tortillas and the masa is too yellow it could be because it contains too much limestone, which makes the masa last longer, but also can negatively affect the taste. If the masa is too white, it could mean it was mixed too long and will produce a dry tortilla.
Here are Yaren's tips on how to taste a tortilla:
1. A tortilla has a front and a back; the front has a thin skin that rolls off when picked at. The back (of a tortilla made in a tortilla machine) has ingrained marks from its time in a rotating oven. While warm, sprinkle the face of it with salt (this is optional).
2. Holding it atop one palm, use the tips of the fingers of your opposite hand to roll it, quickly, into a tight cigar. This takes some practice. If you have the wrong side of the tortilla facing up it won't work and you'll end up with a ripped tortilla.
3. Smell the steam coming off of it, and then take a bite. It should taste of fresh, sweet corn. There shouldn't be any funky odors or flavors. It should not taste sour or fermented in any way. It should not taste bitter or of minerals. It should be pliable, not brittle, soft — but not wet — and a little stretchy. You should want another one immediately.
Yaren says the machine tortillerias use is very important. "In the '50s, Celorio started making these automated machines and they are still the best ones today," he explains. The machines operate a bit like massive pasta makers, rolling the dough into thin strips. Round molds in different diameters are fitted into a part of the machine for cutting out the tortillas. Finally, the machine contains a rotating oven which cooks the cut pieces of masa dough and cools finished, freshly cooked tortillas. A good tortilla will be slightly puffy after it comes out of a tortilla machine, never hard, never doughy.