This chapter reviews ethanol fermentation by the basidiomycetous yeast genus Mrakia. It describes brewing Japanese sake using Mrakia blollopis with sake yeast under low temperature. Cryophilic yeasts of the genus Mrakia have been found in the cold environments worldwide, such as Arctic, Siberia, Alaska, Alps, Apennines, Patagonia, and Antarctica. The information regarding the ethanolic fermentation in basidiomycetous yeasts is limited. Fermentative ability has been reported for Mrakia spp. Many studies have reported the ethanol tolerance and productivity of the conventional yeast Saccharomyces cerevisiae. Sake yeast are known to have the characteristics of high ethanol production and low stress tolerance. The ethanol concentration estimated from the total decrement value in the sake mash was not above 2% (v/v). Moromi, also known as sake mash, is a general term for the starter mixture made of steamed rice, water, and koji fungus.