True Sake is currently flush with seasonal unpasteurized sakes called nama sake. We have gone to great lengths in our attempts to get these fresh "Nuevo sakes" into the market, and True Sake has the largest selection of nama sakes outside of Japan. This truly is one of the first times that seasonal nama sakes have been offered in such quantities in a retail setting. The summer nama selections are from Otokoyama, Ohyama and Umenishiki. These join our other namas from Masumi, Kamoizumi, and Ichinokura.
Most sakes are pasteurized twice – in fact Japanese sake brewers invented pasteurization roughly 200 years before old Louis himself. These pioneers realized that if they heated the sake that it would keep longer and fair better in transportation. To me unpasteurized sakes at times have a 3-dimensional quality that is missing in a "fired" sake. Flavors are bolder and brighter, and as they are living sakes they each vary in how they operate later in their shelf life. Thus there is a sense of mystery as to how they age in the bottle, and one week's flavor could be different from the nexts. That said pasteurization also keeps sake so much more pure than wine that uses sulfites and other preservatives. You really should try a nama sake at some point in your sake career.