When i was child, I used to see my mom cooking food and one question always triggered me why does this chapatis effloresce and then converts into two layers whereas my mom rolled out only one layer of chapatis.
One day i got the answer of these question. I find out that there is a scientific reason behind the it.
We at home usually made the wheat bread or chapatis. Wheat contains a protein called "gluten". Gluten has a tendency to absorb the carbon dioxide.
gluten is a group of proteins called protamins and glutalins. This protein complex supplies 75 - 80% of the total protein in wheat bread.
When wheat flour comes into contact with water and we knead dough.
gluten makes a smooth layer after kneading and absorbs the carbon dioxide present in atmosphere.
When we bake the roti(chapatis) on griddle, carbon dioxide comes out and tries to spread in atmosphere.
In these spreading process, carbon dioxide blooms the upper part of roti on the other side it forms a thick layer.
Enclosed carbon dioxide gas into chapatis and raised heat due to warming of chapatis, two layers are formed.
For flaring the chapatis gluten must contain in the grain. Wheat contains a high amount of gluten whereas other grain like barley, millet has minute amount of protein gluten that is the reason they don't flare and hardly forms two layers.
gluten protein is the main reason of effloresced chapatis that is highly contains by wheat grain.