Name: Nicoyan Corn Tortillas (Made from Nixtamal)
Prep time: 20 min
Cook time: 25 min
Total time: 13 h
Yield: 16 tortillas
Cuisine: Costa Rican
Ingredients: 450g dried field corn (maiz blanco or yellow dent — not sweetcorn, not popcorn); 1½ L water, plus more for rinsing; 1 tbsp cal / pickling lime (food-grade calcium hydroxide) — about 1% of the corn's weight; 1 tsp fine sea salt, added at the grinding stage; Warm water, as needed, to bring the masa together

In Nicoya the tortilla is not a wrapper. It is the floor of the meal — eaten at every one of them, torn and used as a utensil, made from corn that was cooked in lime the night before. The word for that corn is nixtamal, from the Nahuatl, and the process is roughly three thousand years old.

You can make tortillas from a bag of masa harina in fifteen minutes, and they will be fine. This is the other version: whole dried corn, a spoon of cal, and an overnight soak. It takes a night of doing nothing and it produces a tortilla that tastes like corn rather than like flour.

The Longevity Science

Why the lime is the whole point

Maize carries most of its niacin (vitamin B3) in a bound form the human gut cannot absorb. Soaking and cooking the grain in an alkaline solution — traditionally wood ash, now slaked lime — breaks that bond and releases the vitamin, while calcium from the lime is absorbed into the kernel itself. This is not folklore: it is the difference between a population that lives well on maize and one that does not. When maize spread to Europe and the American South without the technique, pellagra followed — the disease of the four Ds, dermatitis, diarrhoea, dementia, death. Mesoamerica, which had nixtamalized for millennia, was spared. A 2026 narrative review of dry-milled corn products confirms the food chemistry and the supportive epidemiology for whole-corn foods, while noting honestly that long-term dose-response trials in humans are still missing.

3,000 yrs

Roughly how long nixtamalization has been practised in Mesoamerica

1 tsp

The amount of lime that separates a complete staple food from a deficiency disease

The Ingredients

450g dried field corn (maiz blanco or yellow dent — not sweetcorn, not popcorn)
1½ L water, plus more for rinsing
1 tbsp cal / pickling lime (food-grade calcium hydroxide) — about 1% of the corn's weight
1 tsp fine sea salt, added at the grinding stage
Warm water, as needed, to bring the masa together

How to Make It

Cook the corn in lime

Rinse the dried corn. In a non-reactive pot, dissolve the cal fully in the water, add the corn, and bring to a gentle simmer. Hold it there 35–45 minutes: you want the kernels slightly softened, not cooked through. The water will turn yellow and smell faintly of cooked corn.

Soak overnight

Take it off the heat, cover, and leave at room temperature for 8–12 hours. This is where the work happens — the pericarp loosens, the niacin is freed, calcium moves in. Do not skip it and do not rush it.

Rinse until the water runs clear

Drain and rinse the corn hard under cold water, rubbing handfuls between your palms. The papery skins will slip off and float away. Rinse three or four times until the water is clear and the corn no longer tastes of soap. This is now nixtamal.

Grind to masa

Grind the wet corn to a smooth dough with the salt — a molino, a food processor with patience, or a heavy-duty blender in small batches. Add warm water a tablespoon at a time. You want the texture of soft play-dough: it should hold a fingerprint without cracking at the edges.

Press and cook

Divide into 16 balls. Press each between two sheets of plastic to about 2mm. Cook on a dry, properly hot comal or skillet: 30 seconds, flip, 45 seconds, flip again — the third turn is when it should puff. Stack them in a cloth as they come off; they steam each other soft.