Japanese Daiginjo sake is a style of sake differing from junmai and ginjo. To create any sake, polished rice – rice which has had the outside layers ground away – is steamed and then fermented. Koji rice – rice on which koji mould has grown – provides enzymes to break the starchy rice down into sugar, and yeast then converts the sugar to alcohol. Daiginjo can also be divided into daiginjo (added alcohol) and junmai daiginjo (no added alcohol).
Daiginjo literally translates as "big ginjo", because a minimum of 50% of the outer layers of rice must be polished away to classify in this category, the highest polishing rate seen in sake production. Note that this is a minimum – some sake breweries have been known to polish to 23%! Because of this daiginjo is often highly prized, and as the best rice is being used other steps are taken to ensure the high quality of the sake. For example, daijingo sake is brewed in smaller tanks than other styles in order to regulate the temperature and fermentation more tightly, while some breweries even have an entirely separate room to make daiginjo koji.
It’s important to remember the level of polish is not a guarantee of quality and lower polished grades of sake can be delicious and more to your taste. So get exploring the wide world of sake. There really is something for everyone.