"Cal" short for cal Mexicana or calcium hydroxide/slaked lime is a food grade, alkaline white powder essential for making traditional corn tortillas. It is used in a process called Nixtamalization, where corn is soaked in water and cal to soften the hulls, improve texture, enhance flavor, and significantly increase nutritional value. It breaks down the tough outer skin (pericarp) of corn kernels, allowing them to absorb water for 10-12 hours after cooking the corn, the corn turns into Nixtamal. Use a volcanic lava stone corn mill, turning your Nixtamal into masa (corn dough)