The fact that a great deal of saké is made from just four ingredients can come as quite a shock. How can a Nigori style have distinct flavors of cherry, coconut or honey? And why do I detect floral and melon notes on the nose of my Daiginjo? The answers generally boil down to two factors: 1) A master brewer’s selection of each type of ingredient and 2) The brewing techniques they utilize to achieve their vision. Below we’ll describe the fab four ingredients, and over the next few months, we’ll break each ingredient down to show how each minute difference can impact the taste, aroma, and quality of any given saké.
Once upon a time in a not too distant past, a critical step in making saké was to chew the rice and spit it into a bucket. This gathered enzymes that aided in breaking down the grain. Thankfully, that step is no longer needed but the process of making koji is still considered the most sacred step in production. Enter Koji (aspergillus oryzae), a mold that grows on the steamed, but cooled rice and in doing so digests it with enzymes that convert the starch into sugars. Koji spores are applied to the steamed rice which is then carefully managed with temperature and humidity controls. Slight shifts in temperature, the length of time, or humidity can mean the difference between a. Koji also adds a good deal of flavor to saké.
Like beer and wine, saké needs yeast to ferment. When rice is polished, washed, steamed and covered with Koji, it turns a hard inconsumable grain into soft, sweet kernels which are fantastic food for yeast. There are about 14 commercial yeast strains available to brewers. Each has its own aroma and flavor profile and interacts with the rice in different ways. Yeast is selected for a very specific desired result. Some of the older brewers in Japan also use proprietary yeast that has been cultivated at their Kura for decades or even centuries. This provides the Kura with uniqueness and when combined with local rice and water provides an example of terroir for saké.
It might seem obvious that water is a necessary ingredient, but it is often overlooked. Sake is about 80% water. Ideal brewing water is low in minerals with little to no iron. Iron will cause saké to darken and create undesirable aromas and flavors. It is also known to hasten the aging process. Manganese is also undesirable as it interacts with light causing saké to become discolored and dampen the overall look and character. Good elements in brewing water include potassium, magnesium and phosphoric acid. These elements aid the propagation of yeast and development of Koji. The taste of the water is also very important as the water used in brewing is also used to dilute sake to achieve greater balance and refine flavor.
Rice, the foundation of saké, comes in many varieties but, like grapes are to wine, only a few are good for brewing saké. Varieties have been cultivated for centuries and today there are about a dozen that are highlighted for saké brewing due to their grain size, hardness (impacts milling), aroma and flavor. Regional varieties of rice differ and are the source of local pride while giving the sake a regional influence on its quality. Knowing the type of rice used in your favorite Sake is not critical, but it can be a great indicator for judging whether the next bottle you purchase is going to please your palate. Back labels & brochures are ideal places to identify what rice was used for your sake. Names that you will most commonly see include Yamadanishiki, Gohyakumangoku and Omachi.