The Ingredients of sake: Rice, Water Koji, Yeast

There are four basic ingredients of sake:  Rice, Water Koji, Yeast.  Each ingredient is essential and is influential to the character of sake.  Sake is rather pure and simple beverage from the standpoint of ingredients.  While wine is simply fermented grape juice, it often contains more additives and natural chemicals than sake.  For example, sulphur, yeast,  sugar, potassium sorbate, calcium carbonate, and acetaldehyde (often the source of headaches).


There are sometimes other ingredients used for sake too.  The optional ingredients for sake include lactic acid and brewer’s alcohol.  Lactic acid helps kill the undesirable bacteria and balance out the sweetness of sake by adding acidity.  Another optional ingredient is added alcohol.  Historically, brewers added alcohol to stretch their product when there was a rice shortage after World War II.  Today, this brewer’s alcohol is applied not for alcohol contact, but rather for balance to the final product.  Brewer’s alcohol is added sparingly solely for the purpose to enhance flavors and aroma.


Rice is the first ingredient that comes to mind when most consider sake ingredients. Rice for sake (sakamai) is different than table rice used for eating.  Sake rice is larger and more difficult to grow than table rice.  After rice is harvested in the fall, rice milled or polished.  This process removes 30-65% of the outer portion of the rice grain.  The larger size of sake rice enables the grain to better withhold the milling process without breaking during the pressure and heat of the milling machine.  Also the composition of the rice grain is not homogenous.  The outside part of the rice contains fat and protein.  The center of the rice grain contains starch which is better for fermentation.


There are approximately 100 different types of sake rice.  However, it is possible to make sake from table rice.  The ability to make a quality sake from table rice relies more on the skill level of the brewer.


Sake is composed of nearly 80% water.  The location of most sake breweries is based on the location and access of high quality water.  Japan is rich with natural high quality water.  Water can differ based on region.  Soft water allows for a slow fermentation process and a generally softer finish on the palate.  Hard water provides a more robust fermentation process.  In general, most of Japan’s water sources are considered soft by world standards.  A high quality water source will increase the ability of working with yeast and koji.  Water with minerals such as iron or magnese will discolor sake and produce undesirable flavors.


While rice is a key ingredient determining flavor, yeast is the ingredient that impacts aroma.  Similar to beer and wine, the purpose of yeast is to convert sugar to alcohol. Yeast types for sake are limited and controlled the Japanese government.


Koji is a mold.  While the term mold evokes a negative image.  The koji mold is harmless to the body and is actually a nutrient rich additive,  Koji mold is also a key ingredient for certain fermented food products such as soy and miso.  The purpose of koji is to convert starch to sugar.  Koji is applied to steamed rice in a powdered form.  While koji is not key ingredient for flavor or aroma like rice, yeast and water, it is crucial for the brewing process.  The process is a delicate and precision is crucial to ensure temperature controls in the dedicated koji room.


The ingredients of sake are relatively few.  However the ability to use these ingredients to produce sake is something that requires great skill.  While some of these ingredients today can be transferred to other parts of the world, Japanese sake is difficult to replicate outside of Japan.