Mechanical Leavening

Mechanical leavening simply means that the mixing method employed in a recipe functions as the leavening. Biscuit, puff pastry, croissant, danish, shortcrust, and sweetcrust doughs are leavened mechanically. (Croissant and danish doughs are leavened also with yeast, a natural leavener. Biscuits are leavened with an additional chemical leavener.)

Leaving fat in chunks throughout the dough or folded into neat layers between dough is the mechanical leavening method behind pie, biscuit, scone, puff pastry, croissant, and danish doughs; during baking, the fat dissolves and air pockets are left behind.