What nixtamal is, and why it changes the flavour
Nixtamalization is the process that turns a hard kernel of corn into dough: the grain is cooked in water with lime, usually slaked lime, for half an hour or more, then left to soak overnight. The lime softens the pericarp, the outer skin of the kernel, and releases niacin and other nutrients that raw corn does not deliver in the same way. The technique is Mesoamerican, thousands of years old, and it explains why corn, rather than wheat, sustained entire diets in the region without causing the deficiencies that do appear where corn is eaten without being nixtamalized.
The process is simple in principle but demands time, water, lime and fresh corn, and that is where the difference begins. Nixtamalizing at home or at a neighbourhood mill takes hours and produces a dough that smells of cooked corn, with colour and texture that shift depending on the grain used. Replacing that step with an industrial corn flour, already nixtamalized and dehydrated, to which you simply add water, saves time but changes the outcome: the dough is more uniform, easier for a machine to handle, and flatter in flavour. That difference, small in appearance, is what separates a memorable tortilla from a merely acceptable one.
The same word, three different products
Mexico has at least three products living under the same name, and confusing them explains much of the disappointment felt by anyone who remembers a better tortilla. There is the neighbourhood tortillería tortilla, machine-made from a dough that usually blends its own nixtamal with industrial flour in variable proportions. There is the supermarket tortilla, made almost always from one hundred percent industrial corn flour, with preservatives so it survives weeks in the packet. And there is the market tortilla, made by hand or on a small mill, from native corn bought directly from a grower, nixtamalized the same day and sold while still warm.
The difference shows up in the mouth before any technical explanation is needed. The industrial tortilla is elastic, folds without tearing and tastes of very little, because it is designed to travel and to sit on a shelf, not to carry the flavour of corn. The mixed-tortillería version sits in between, with some corn flavour but also a uniformity that gives away the added flour. The market one tears easily, has an uneven texture, a colour that shifts from one batch to the next, and a flavour of cooked corn that the other two simply lack, because they never stopped fully being it.
Native corn, and the variety almost nobody sees
The corn grown in Mexico is not a single crop but hundreds of native varieties, shaped over centuries to a particular valley, altitude or soil type. There is blue corn, red, white, yellow and almost black, each with its own flavour and its own behaviour when cooked and nixtamalized. Communities in Oaxaca, Puebla and central Mexico still plant dozens of these varieties, saving seed from one harvest to the next just as their grandparents did. That diversity is why a blue tortilla from a market stall does not taste the same as a white one from the very same stand.
The corn bought by the large flour mills is almost always a white hybrid variety, chosen for yield and for behaving consistently in a machine, not for flavour. Native corn, by contrast, is grown on small plots, yields less per hectare and takes longer to cook during nixtamalization, which raises the price of every tortilla made from it. That is why it only turns up at specific market stalls, in tortillerías that order it directly from a grower, and in a few restaurants that advertise it as a selling point. Finding it takes effort; it is not in the supermarket or in the nearest tortillería on any corner.
What almost nobody says out loud
Industrial corn flour spread across the country from the nineteen-seventies onward, first as a practical option in areas without a mill and later as the standard input in most urban tortillerías, which blend it into their own nixtamal to cut costs and speed up production. Decades later, the result is that a good part of an entire generation has never tasted a tortilla made one hundred percent from freshly nixtamalized native corn. What used to be the ordinary tortilla of any household became a niche product, sold at specific stalls and priced noticeably higher than the everyday tortilla.
This does not mean the good tortilla has vanished, only that it stopped being on every corner without effort. Native corn, home or small-mill nixtamal and the hands of someone pressing by hand still exist, but now they have to be sought out, almost always at a market and almost never at the tortillería closest to the hotel. Paying more for that tortilla is not a rip-off: it reflects corn that cost more, a slower process and less volume per seller. The disappointment comes from expecting that flavour at the price of the industrial version, and that is no longer realistic in almost any large city.
How to find a good tortilla, and how to carry it
The simplest way to find a good tortilla is to go to a market and look for the stall where someone presses by hand, or where a line of people is waiting, because queues rarely lie. Asking whether the tortilla is made from native corn or contains added flour usually gets a more honest answer at a small stall than at a chain. Oaxaca is a good place for this search: the city has a very strong native-corn culture, sustained by the tradition of the tlayuda and by markets where several families still sell corn from their own plots, not bought from a mill.
Once bought, good tortillas behave differently from industrial ones and deserve different treatment. Carry them wrapped in a cloth napkin inside a basket or a lidded container that keeps the steam in, never in a sealed plastic bag, because they sweat and turn gummy. Eat them the same day, since without preservatives they harden fast; whatever is left over gets reheated on a comal, never in a microwave, to bring back some flexibility. Do not store them in the fridge, which speeds up the hardening of the starch, and do not try to bring them home from a trip: they are a same-day, same-place product.
The mistakes people keep making
The first mistake is assuming that any tortillería sells an artisanal product just because it makes the tortillas on the spot; many use the same industrial flour as the supermarket, only freshly made. The second is trusting colour alone: a blue tortilla is not automatically native corn, because there is also industrial flour dyed to imitate it, and colour only guarantees something when bought directly from whoever made it. The third is buying more than needed, letting the rest dry out in a backpack or a fridge, when the right amount is whatever gets eaten in a single meal.
Another common mistake is storing tortillas in the fridge to make them 'last longer': the cold speeds up starch retrogradation and turns them gummy far sooner than they would go from simply drying out at room temperature. High price is also mistaken for guaranteed quality, when in reality some places charge more simply for being near tourist areas, without the corn behind them being any different. Finally, plenty of people give up the search after trying a bad hotel tortilla and assume the flavour they remember no longer exists anywhere, when really all it took was walking a few blocks to the nearest market.
What people always ask
Six concrete questions about corn, nixtamal and tortillas, answered without gilding what is no longer as it used to be. They run from the most practical, how to recognise a good tortilla on the spot, to the most uncomfortable, why most of what is sold today is not what people remember. The order matters little because all six tend to come up together, usually after the first disappointment with a hotel or chain tortilla, when someone starts wondering whether the flavour they are after actually still exists somewhere in the city.
It is worth adding something that does not fit in a short answer. Native corn and nixtamal made the way it has always been made are not going to disappear entirely, because whole communities, especially in Oaxaca and central Mexico, keep planting and grinding exactly as they did a century ago. What can disappear is the habit of finding it without effort, without searching, without paying a little more. Accepting that, and planning the trip with a couple of markets and one trusted tortillería already identified, is the difference between eating well and simply eating whatever happened to be nearby.