Ouch. There's so much conflicting information from what you might think are reputable sources on the differences between grits and polenta. Without claiming any expertise, here's what I know after some frustrating research some years ago:
Once those clever people in Mexico figured out how to nixtamalize corn, it caught on in the south, and grits were typically made from what is called "dent" or nixtamalized corn. It can be white or yellow corn or even other colors. Polenta, which was an Italian form of cornmeal mush, was made from "field corn" and not nixtamalized. The grind, whether coarse, medium, fine or extra fine may be a matter or preference, as noted above, in northern and southern Italy, There is certainly some variety in the grind of southern grits. Maybe different stones grind differently. Maybe once upon a time you could take your corn to the mill and ask for it to be ground however you wanted. To overgeneralize, I get the sense that the polenta preferred by Italians in America is often a finer grind than southern grits. I like my grits toward the coarser end of the spectrum, which usually means that ithey need almost an hour to cook properly.
I like white grits a little more and my husband prefers yellow, so I buy both and we switch off. Variety is good! I do think they taste a little different, but then lots of factors are in play there, some cultural and some psychological as with any subtle judgements. Personally I get the sense that there is a snootiness factor about white corn, which may have originated from any number of truths or half-truths. Maybe white corn was more expensive and more temperamental to grow, and therefore gained value.. Maybe it was just more white. Maybe it tastes a little more delicate or "refined." I'm not really sure, and I happily eat both. Jump in, anyone with an opinion about this.
I've bought grits from a variety of mail order sources. Mostly they say nothing about what kind of corn they use or whether it has been nixtamalized, so I don't assume anything, but I simply go for whatever seems to be the freshest and best quality and tastes great. I do think the flavor and texture of stone ground grits from a reputable mill has a more dynamic taste that the Italian imported polenta that you get in a box. Much as I love many of Bob's products, their labelling can be very confusing. Their Corn Grits look yellow, so why don't they label them Yellow Corn Grits to distinguish them clearly from their White Corn Grits? And are there grits that are not made from corn? Get it together, Bob. I like Bob's cornmeal though, for making corn bread as it is kind of a medium grind and kind of toothy.
Geechie Boy Mill, where I order my grits, is now selling blue grits. I haven't tried it.
