Traditional Mexican Culinary technique to make Corn Masa after Nixtamalization, grinded on a Metate 

Traditional Mexican Culinary technique to make Corn Masa after Nixtamalization, grinded on a Metate;
Please allow me to show and share with you, how to make after a Nixtamalization an authentic Mexican Masa on an authentic Mexican prehispanic culinary tool, called ‘Metate’.
General Information:
Corn is native to Central America and some of the oldest corn seeds found in a cave are older than 10thousand years.
There are many different varieties and types of corn, I could not think of an color which you would not find in corn seeds, including black, purple, blue, green, red, yellow, white, pink and others
To make an authentic Nixtamal and Masa for Tortillas, we always use dry Corn seeds, not fresh Corn
Masa is the base to make corn tortillas but also many other things like Tamales, Tlacoyos, Sopes, Gorditas, Corundas, Huaraches, Atole drinks and many other preparations of Central American cuisine
The way to make authentic Masa is the same way the Nahua (Aztec) people had made it, the process is called ‘Nixtamalization’ and also the industry which makes comercial dehydrated masa, uses the same cooking process and technique
How nixtamalization was discovered is not known, but one possibility may have been through the use of hot stones to boil maize in early cultures, or when they used water from lakes with high amounts of minerals.
To cook the corn, don't use aluminum cooking ware that is not so great and in fact dangerous. Calcium Hydroxide + Aluminum = Hydrogen Gas and you don't want hydrogen gas in your kitchen with an open flame. Stainless Steel is the best or like traditional in the old days in a claypot.
How to make Masa from Nixtamal;
The most authentic Tool and already since prehispanic times to make masa, is of course a Metate grinder which is a tool made from natural rocks usually vulcanic. (The darker, the best, because it means its older aged volcanic rock material)
Once the old world got connected to the new world and different metals had been introduced to the culture, also tools changed, now we can find hand or electric corn grinder which would be my second choice after a Metate grinder.
Kitchen aid grinder or food processor would probably also work after lots of effort and time, but to be honest, there is never going to be a better masa than made on a Metate rock grinder, it's the authentic traditional ancestry way and the flavor and texture are just different but perfect when you use these tools, even it takes lots of work.
To make the masa all you need to do is grind the cooked corn, choosing one of the before mentioned tools, if the dough is too dry, add a little bit of the liquid from the cooking process. The more you grind, the finer or cursor gets the dough, the dough should always hold together like a playdough and should not stick on your dry hands.
Use you masa right away to make your tortillas or whatever you have planned to make with it. You should not store fresh made Masa for more than 24 hours, because it gets sour / bad fast.