Dry yeast contains microscopic fungal organisms that have lost activity but can be reactivated and are used for fermenting dough. Typically sold in packets, this yeast becomes active again when mixed with flour and water, allowing the dough to rise. It is commonly used in the production of bread, pizza dough, cakes, and other baked goods.

Dry yeast is preferred in home and professional kitchens due to its ease of use and long shelf life. Additionally, different types are available (e.g., instant yeast and active dry yeast), providing flexibility to adapt to various recipes.