For yeast-based and sponge (such as sourdough) breads, a common production technique is the dough is mixed, kneaded, and then left to rise. Many bread doughs call for a second stage, where the dough is kneaded again, shaped into the final form, and left to rise a final time (or proofed) before baking. Kneading is the process of working a dough to produce a smooth, elastic dough by developing gluten. This process is both temperature and time-dependent; temperatures that are either too hot or too cold will cause the yeast to not develop, and rising times that are either too short or too long will affect the final product.