Soybean soaking is a traditional process that is mainly used to soften the grains and to facilitate their subsequent cooking. In the Illinois process that is used in the production of soymilk, the soybean grains are soaked for 12 h at room temperature (Nelson, Steinberg, & Wei, 1976). Texture changes in the grains result from water absorption, which is affected by the soaking time and temperature (Pan & Tangratanavalee, 2003), and continue throughout the cooking step, with the added effect of the cooking temperature. Lengthy soaking time until reaching equilibrium moisture content in the soaked soybeans is not necessary to promote additional softening of the grains because it does not produce further improvements in cooking rate or cooking quality of the soybeans