The elastic, chewy texture of everyday bread is all thanks to a protein complex called gluten. Gluten does not exist in dry flour; it is formed when two proteins, glutenin and gliadin, are mixed with water and kneaded. As you knead the dough, these proteins uncoil and link together to form a strong, elastic network. This network acts like a series of tiny balloons that trap carbon dioxide gas produced by yeast. Without gluten, the gas would escape, and the bread would be flat and dense. This is why gluten-free baking requires alternative binders like xanthan gum to mimic this 'trapping' effect. The strength of the gluten network determines whether a bread is soft (like brioche) or tough and chewy (like a sourdough baguette).