Air pockets in naan dough are primarily caused by the steam produced during baking, which gets trapped within the gluten structure of the dough. This is often enhanced by high heat and the presence of moisture.
Naan dough, typically made with flour, water, yeast, and sometimes yogurt or milk, undergoes fermentation. During this process, yeast produces carbon dioxide gas, which creates small bubbles within the dough. When the naan is cooked in a very hot tandoor oven or on a hot griddle, the high heat causes the moisture within the dough to rapidly turn into steam. This steam expands the existing gas bubbles, creating larger air pockets. The gluten in the dough, a protein network, stretches and traps the steam, preventing it from escaping. The rapid cooking also sets the structure of the naan quickly, solidifying the air pockets. Factors that contribute to larger air pockets include:
High Heat: Intense heat causes rapid steam production.
Moisture Content: A wetter dough will produce more steam.
Gluten Development: Well-developed gluten traps the steam effectively.
Yeast Activity: More active yeast produces more gas initially.
To control the size and number of air pockets, adjust the hydration level of your dough. A slightly drier dough will produce fewer and smaller air pockets. Also, ensure your cooking surface is hot enough to create steam quickly, but not so hot that it burns the naan before it has a chance to puff up.