Mitoku seitan is made the traditional way by kneading whole wheat dough to develop the gluten, rinsing the dough to remove the starch (carbohydrates) and bran, thus concentrating the gluten (protein) of the wheat, and finally simmering the gluten in a savory broth. Seitan is not difficult to make at home, but the process is labor intense and rather messy. Making delicious seitan in a small shop requires a great deal of experience and some simple equipment.
Wheat is preeminent among the grains,because it is the only one whose endosperm protein interacts to form a gluten strong enough to bind together into a tight mass. Gluten is both plastic and elastic; that is, it will both change its shape under pressure and tend to reassume its original shape when pressure is removed. It is this elastic and plastic property of wheat gluten that is utilized during the seitan making process.
At the Mitoku shop workers first place several hundred pounds of high gluten, whole wheat flour in the seitan or gluten machine. This is a stainless steel tank with several rotating arms or paddles at the bottom. Next, the machine is turned on while a specific amount of water is added. When wheat flour is mixed with water, the gluten protein begins to unfold into a random network. Water molecules separate and lubricate the long chains of gluten, which begin to stick together to form visible strands. Meanwhile, the wheat bran and starch turn the water into a milky beige slurry which is carefully discharged from the bottom of the seitan machine. (The liquid is saved and used as animal feed or to make other related foods.) Fresh water is added and drained several times as the constant motion of the paddles keeps concentrating the wheat gluten as it sticks together into a large, rubbery mass at the bottom of the seitan machine. Finally, after a few hours of mixing and several rinsings with fresh water, the concentrated gluten mass is removed from the machine, cut up into small pieces and cooked in a savory broth of kombu and soy sauce. The seasoned gluten is then packed in jars which are placed in a large pressure cooker (retort) and cooked for a specific time to ensure sterilization.