© 2016 Elsevier Ltd There is increasing interest in the food industry in the development of new or improved commercially available food products. New methods to test the characteristics of raw materials and products are necessary. The viscosity (consistency or texture) of foods is an important rheological variable during processing because it influences the equipment design necessary for food production. Additionally, viscosity determines functionality and consumer acceptance of foods. This review focuses on extensional viscosity characterization as a tool to aim the development of novel and improved food products and processes. Extensional deformation is involved in processes as extrusion, film blowing, and fiber spinning, but it is also important in determining and understanding interactions among food components (e.g., proteins, polysaccharides, and lipids) in food products (e.g., bread, pasta, syrups, snacks, and salad dressings).