Pre-Columbian Mesoamerica; earliest evidence circa 1500–1200 BCE in the Soconusco region of southern Mexico and Guatemala. The Aztec (Mexica) term is nextamalli (from nextli, lime ashes, and tamalli, unformed corn dough).
Nixtamalization is the pre-Columbian process of cooking dried maize kernels in an alkaline solution of water and calcium hydroxide (cal, slaked lime — not citrus) to transform the grain chemically, nutritionally, and structurally. The process liberates niacin (vitamin B3) bound in the maize pericarp, making it bioavailable and preventing pellagra. Without nixtamalization, populations eating maize as a staple suffer niacin deficiency; this is why non-nixtamalized maize diets in colonial Europe caused epidemic pellagra. The chemistry: cal raises the pH of the cooking water to approximately 11–12, breaking the hemicellulose bonds in the pericarp (outer skin), gelatinising the starch partially, and cross-linking proteins to create a pliable, extensible masa. The distinctive flavour — earthy, mineral, complex — comes from the Maillard products of partially gelatinised starch interacting with the alkaline minerals. Masa Harina (Maseca brand) is pre-nixtamalized dried masa flour; fresh nixtamal ground on a stone metate or electric mill produces a masa of categorically superior flavour and texture.
Properly nixtamalized masa has a complex minerality, faint earthiness, and a sweetness from partially gelatinised starch that is entirely absent from non-nixtamalized maize flour. This flavour is the foundation of all Mexican corn-based cuisine.
Ratio of cal to water to maize: approximately 1 tablespoon cal per litre of water per kilogram of maize Cooking time: 20–45 minutes simmering, never boiling vigorously — boiling breaks the kernels prematurely Resting (nejayote): the cooked maize must rest in its cooking liquid (nejayote) for 8–24 hours — this is where the mineral absorption and full pericarp softening occurs Rinsing: the cooked, rested nixtamal must be rinsed thoroughly — residual nejayote bitterness ruins the masa Freshly ground nixtamal produces masa of incomparably superior flavour to reconstituted Maseca
Test cal alkalinity by pressing a small amount onto moistened pH paper — you need pH 11–12 for effective nixtamalization The nejayote (alkaline cooking liquid) has culinary uses: it tenderises beans, is used as a mordant in traditional dyeing, and forms the base of some regional atoles For blue corn nixtamal, the anthocyanins react with the alkaline cal to produce a grey-purple colour — this is correct, not a fault Freshly nixtamalized maize ground within 24 hours of cooking produces masa with the most developed flavour
Using baking soda as a cal substitute — it produces a pale colour and off-flavour without the full mineral transformation Skipping the overnight rest — the masa will lack extensibility and the tortilla will not puff Over-cooking to the point where kernels split and lose their structural integrity Under-rinsing — residual alkaline bitterness is irreversible Using citrus lime (Citrus aurantifolia) instead of calcium hydroxide (cal) — a persistent translation error in English-language recipes
Diana Kennedy, The Art of Mexican Cooking (1989); Sandor Katz, The Art of Fermentation; Jeffrey Pilcher, Que Vivan Los Tamales! Food and the Making of Mexican Identity