Many experienced chapati makers have observed that I’m fiddling with tradition here. It’s true. Indeed I am varying the flours and the liquids in order to get to a softer, more toothsome homemade product. Don’t infer from that statement that I don’t think traditional recipes give good results, but ingredients and…ehem…the manipulators of those ingredients, vary highly from place to place. I should be using atta, traditional Indian chapati flour, but I can get any. As a result the all-whole wheat flour and all-water recipes weren’t delivering bread anywhere near as good as I remember from the real Indian meals I’ve had.
So why the white flour? Mainly because I want more gluten to develop in the dough. It’s not that whole wheat flour doesn’t have plenty of gluten in it, it does. Indeed it has everything in it, and that’s the problem. The bits bran that are in there — the ground pieces of the wheat berry husk — are hard and sharp, and they have a way of cutting up gluten networks as they form. That means a less elastic dough, one that’s more likely to rupture than expand and stretch when it cooks. So I dilute it with white flour to give me the flexibility I want while retaining much of the wheat flavor.
As for the milk, the fats and sugars add some tenderness. The yogurt does all that plus it introduces more flavor. As I mentioned, flat breads are not fermented, or if they are not for very long. Yogurt, however, is fermented, and by many of the same sorts of microbes (lactic acid bacteria) that are active in a long-rising breads. Thus you get the moisture, the tenderness and the flavor all in one handy package. It’s not necessarily traditional, but I tend to like the results. I’ll put up the photos shortly!