There are many steps in the sake making process, and some brewers may choose to skip some to achieve a desired flavor. “Roka” is the process of clarifying the liquid further after pressing. While roka removes some finer particles that make the sake more susceptible to aging and changing color, the brewery may decide to forego this step to keep more flavor and character. The resulting sake is called “muroka,” with the prefix “mu-” literally meaning “without.”