Gluten is a protein in the flour that makes pizza dough stretchy, and biscuits too tough. Gluten can be the bread baker's friend, and the pastry chef's enemy.
Gluten and Kinds of FlourThe main difference in the kinds of flour that are most commonly talked about is the amount of gluten.
- Bread Flour: High gluten, made from hard wheat. Makes nice and stretchy dough if you knead the dough. Great for breads and pizza crusts.
- All Purpose Flour: Made of a mixture of hard and soft wheats. Meant to work ok for any kind of baking. Knead the dough well, and it will get stretchy for bread baking. Mix it gently, and you can make tender biscuits and cookies.
- Cake Flour: Low glute, made from soft wheat. Usually bleached, which tends to make it even better for baking a nice tender cake.
There are also specialty flours, like Semolina, which has extra high gluten content. This flour is made from Duram wheat, and is used to make pasta. Some other grains besides wheat contain enough gluten to produce bread.
If you start mixing it harder, it will start getting stretchy and form into a ball. At the point that you are pushing on a ball of dough, folding, flattening, stretching it, you are "kneading" it. The stretchyness is from the wet gluten, which begins forming into nice rubberband-like strands. As the gluten "develops", the dough looses the stickiness, becoming smooth, soft, and pliable.