Hypothesis 1: Masa Harina is treated with lime. Mealies is not. Maybe this makes the masa farina soak up the liquid better to make a paste or something.
Test1: Ask Aunt Lorraine
Result1: Lorraine turned me on to the most amazing cookbook ever, Authentic Mexican: Regional Cooking from the Heart of Mexico by Rick and Deann Bayliss. Besides amazing step-by-step instructions to go from the cornfield all the way through to tortilla, the book is illustrated with gorgeous pen and ink drawings of every tortilla press, herb, ingredient, how it looks in different parts of Mexico, etc. A coffee table book almost.
Discussion1: Results are inconclusive, although since it is possible to make tortillas from corn without drying/grinding I think the lime is probably not the main issue. It seems to be an additive to aid in dehydration.
Unexpected result1: Elsie and Esperanza (two of Grammy's caretakers) spontaneously went out and bought me a fantastic tortilla press and 2kg of Instant Masa. Esperanza showed me how to shape tortillas by hand in the El Salvadorian way. Elsie is Mexican and uses the press. Between them I think I got the hang of it! Hand shaping will take more practice.
Hypothesis2: Geological factors, such as grain size and/or grain shape, determine the behavior of the maize-water slurry.
Test2a: Examine grainsize.
Result2a: On the left you will see the (California-bought, yes I carried it back with me) Masa Harina. On the right, South African instant mealie meal. The grain size discrepancy is only too clear.
Test2b: Examine grain shape/surface texture.
Result 2b: Although the camera can't capture the grain shape, mealies is clearly angular, smooth, and has a very low angle of internal friction. Conversely, masa harina is considerably finer and grain shape is flattened and rough. Masa harina has a higher angle of internal friction.
Discussion2: The grain size and shape of masa harina seems to be such that there is a slight attraction between masa particles, producing balling behaviours texturally not unlike floculated clays. Unclear whether this is a static effect or an interaction with atmospheric moisture.
Hypothesis3: Due to grain size, masa harina aborbs water much faster to make an instant masa. Water will diffuse into coarser mealie flour particles over a longer time period, ultimately producing masa
Test3: Soak the mealies.
(Meanwhile, wet the masa harina, make the masa, make 8 tortillas, eat 4!)
Result3: Hard wet mealies.
Still pending. I think I will have to purchase a stone mill and crush the mealie flour down to a flat, fine flour and try that. In the meantime I went to the La Crusette store and improved the tortilla factory in my kitchen with a real cast iron skillet:
Which makes an amazing difference!