If you happen to be gazing down at your tortilla chip and notice it is blue, it’s very likely made from a special type of blue corn flour known as harinilla, or harina azul. This is not the same type of blue corn flour that has the grainy texture of regular corn meal. The grind is much finer and goes through a special process in order to produce harinilla
Harinilla has a special flavor caused by soaking dried blue corn kernels with lime, or calcium hydroxide. This soaking process results in the corn kernel expanding so that the hulls become loose and separate from the inside of the kernels. The resultant flour can also be called hominy, but harinilla, and its companion, masa harina, made of yellow or white corn, are slightly different. Hominy is frequently made with other solutions or chemicals with alkaline properties. Traditional harinilla uses only lime in the process.
Harinilla and masa harina are important staples in Mexican cuisine. They are used to make the outside coating of tamales, to make tortillas, and they are frequently added as a thickening agent to soups and stews. While you can substitute regular yellow or blue corn flour in recipes calling for harinilla, you must mill the flour first in order to produce the finer grind. This can be accomplished by using a fairly sturdy blender, a food processor, or even a coffee grinder devoted to milling. You don’t want to use a coffee grinder in which you regularly grind beans, as some of the oils of the beans will stay in the grinder and result in coffee flavored flour.
When you buy this type of flour, the color can look light blue to grayish. As it cooks it will turn a deeper blue. It can be fascinating to cook with it, and extremely exciting for kids who loved colored food. Adding harinilla to cornbread, or using it to make hominy grits can make these foods quite appealing and a nice change to your usual meals.
The best place to find this special flour if you live in the US is at Mexican and South American grocery stores. In some areas with large populations of Mexican immigrants, you may also find it carried in local grocery stores. Just remember not to confuse this flour with blue corn flour or corn meal. The coarser grind of corn meal can change the texture and cooking times of food if it is substituted. For the real deal, look for the finely ground corn flour. If you’ve had no luck finding it near home, you can order it on the Internet from a number of different sites.