Great-tasting Mexican tortillas and tamales are made with a dough called masa, which consists of specially processed corn. This method, called nixtamalization, intimidates many a U.S. cook. Which is a shame, since it is very easy and absolutely approachable. To do it, one boils hard corn in a mixture of calcium carbonate ("Mexican cal") and water, then grinds the softened kernels in a food processor. Any corn can be nixtamalized, but after many tests we've settled on white popcorn. It's inexpensive, readily available and responds beautifully.
Yield: enough masa to make 10, five-inch diameter tortillas.
Time to make: 45 minutes active. Boiled corn must hydrate all day.
Equipment needed: Measuring cups and spoons. 4-quart saucepan. Large wire mesh colander. Stirring spoon. Food processor. Spatula.
1) Add the water to a 2-quart saucepan. Dissolve calcium carbonate in the measured water. CAUTION: calcium carbonate is a skin, eye and nose irritant. Follow precautions on packaging. Heat on high until water just boils, then add the corn. Return to a boil then turn down to a simmer. Corn will change color, becoming cardboard tan. (see left photo) Cover pan.
2) Allow corn to simmer at least 60 minutes, or until kernels swell noticeably with some rupturing. Remove from heat but keep saucepan covered. Set aside for the remainder of the day, or overnight.
3) Pour contents into a large wire-mesh colander. Rinse thoroughly, rubbing corn to remove slick sticky "skin". When corn no longer feels sticky, drain and transfer to the food processor. Add the salt and process for about 15 minutes, stopping occasionally to wipe down sides with a spatula. It will seem that no progress is being made but eventually the dough will come together in a sticky cylinder that adheres to the side of the food processor and spins. (see right photo) The masa is now complete. If too dry, add very small amounts of water just before shaping into final products. If too wet, add small amounts of corn starch.
Masa may be used to make tortillas, gorditas, tamales, rosquillas and more. It can be stored in the refrigerator. It should be well-sealed since it dries out quite easily.