I've been making a lot of Mexican food lately. That's partly because I have a stash of fresh chillies and tomatillos that I brought back from a trip last month to the United States, but it's mostly because of my new tortilla press, which took up a hefty 3kg of luggage allowance.
Tortillas - at least the type made from ground cornmeal - are probably the easiest, fastest type of "bread" you can make. It's made of masa harina, which is often called cornflour, although it is a specific type. It's not the kind of cornflour used to thicken sauces, nor is it just a finer grind of the dried corn that's used to make polenta or cornbread.
Masa harina is made of dried corn soaked in slaked lime, also known as cal or calcium hydroxide. When it's consumed on its own, corn isn't very nutritious, because our bodies have a hard time digesting it. The Aztecs somehow figured out that soaking dried corn in water that contained wood ash made it easier to digest, and therefore it was much more nutritious. The term used for the process of treating the kernels with lime is "nixtamalisation".
The best corn tortillas (and other nixtamal ground-corn products) are made from kernels that are freshly ground into a slightly coarse dough that has to be used within a day, as it's highly perishable and the texture changes when it's refrigerated. The best texture is achieved by hand-patting this dough into thin circles.
Fresh masa is only available in places where there is a large Mexican community (which unfortunately rules out Hong Kong) and hand-patting the dough into circles thin enough to be called a tortilla is much harder than it looks (trust me, I've tried). So that means we have to rely on commercially ground cornflour and a tortilla press (or a very heavy pan and a lot of elbow-grease).
Accompanying my tortilla press was a 2kg bag of Maseca - the brand of masa harina sold in most supermarkets in southern California. I compared it to the Bob's Red Mill brand version from City'super: they were very different.
Maseca flour is made of white corn and is very finely ground; Bob's Red Mill is made from yellow corn and is slightly grainy. I'm still deciding which one I prefer: the Maseca smells "cornier" and fresher, but when mixed with water and made into a tortilla, the texture is slightly gummy. Bob's Red Mill doesn't smell as corny and although the finished texture is better, the tortillas dry out faster. I might end up mixing the two to get the best of both products.
It took me a while before I started making really good corn tortillas using the press: one night, I stayed up until 1am pressing three dozen tortillas that I made into taquitos and chips for a lunch the next day (they needed to dry slightly overnight, because I was going to fry them, and too-fresh tortillas would have absorbed too much oil).
Most recipes tell you to mix the flour with slightly hot water, adding just enough so the dough is malleable. I find it's better to add a little extra water then let the dough stand, tightly covered with cling-film (because the dough dries out very quickly) for about 10 minutes. The extra moisture makes the pressed dough less prone to cracking at the edges, and makes them puff slightly when cooked. I weighed out the balls of dough and pressed them between two plastic sheets (I used a zip-lock bag slit open on three sides). Because the pressure in the press isn't even (which means the tortilla is thinner on one side), you need to press it 80 per cent of the way then rotate it before pressing it completely down.
If you don't have a tortilla press, put each dough ball between the plastic sheets and press them under a very heavy pan.
Mexican cooks would use a comal (a smooth flat griddle often made of clay) to cook the tortillas: I use a tawa - a round, cast-iron griddle that I purchased from an Indian supplies market in Wan Chai. The heat under the griddle needs to be right: if it's too hot, the exterior gets burned before the interior is fully cooked; if it's too cold, the tortilla sticks and dries out. The tortilla is ready to flip as soon as it lifts away from the griddle without sticking.
After cooking each tortilla, stack them on a clean dishcloth, wrapping the cloth round them to keep the heat in: this softens the tortillas and makes them malleable. The taste and texture of tortillas is best when fresh, but if you need to reheat them, do it quickly on the griddle, and again, wrap them in a dish towel so they soften.
Truc (tryk): noun, masculine, trick, gimmick, device. A French word for a chef's secret.