What is Sake?
Four ingredients are needed to make sake: rice, water, yeast and koji. This seems pretty simple but appearances are deceiving. Special rice, called sakamai, is used to make sake and is prepared by polishing to a greater or lesser extent. The quality of the water also differs within each region. The dissolved minerals have a lot of influence on the taste and fermentation of the sake. Yeast is another ingredient that contributes to the aroma components of sake. Individual breweries and regions developed their own yeast strains. The fourth ingredient - koji - is the fungus that is distributed over the rice to convert the starch into sugar. Here, too, different koji species are used. Together with the brewing process, and the choices made, determines the unique taste profile of each sake.
Sake is often called "rice wine" because, like wine, it contains unique variations of flavors with subtle aromas. In addition, it is often drunk as wine. Sake is also compared to beer because it shares a similar brewing process. However, brewing sake is much more complex and requires a process called "multiple parallel fermentation" to stimulate the conversion of starch into sugar and sugar into alcohol simultaneously (not sequentially as with beer).
Brewing sake requires experienced master brewers to control the delicate balance during the production process. Every detail - from selecting the right combination of ingredients to polishing, washing and steaming the rice, to closely monitoring the progress of fermentation - plays into the taste, aroma and final result.
The sake brewing process simply comes down to the next steps.
- Polishing: To remove impurities such as fat and proteins, rice is first polished.
- Washing and soaking: The remaining rice cores are then washed and soaked.
- Steaming: After soaking, the rice is steamed.
- Koji: After steaming, some of the rice is sprinkled with koji. This noble fungus invades the now porous rice and converts the starch into sugars.
- Yeast starter: Steamed rice and yeast are added to this koji rice for the formation of the yeast starter or shubo.
- Alcohol formation: in 2 to 4 weeks, by the production or addition of lactic acid, the optimal conditions are created for the yeast cells to be able to do their work, transforming sugar into alcohol. The longer this process the more complex the taste.
- Scaling-up: water and more rice are then added at different stages. This creates the final brewing mass. The uniqueness of sake is that the sugar formation and alcohol formation in this mass take place simultaneously. This is also the reason that sake of all alcoholic beverages, only by fermentation, contains the highest percentage of alcohol.
- Presses: after about a month, the mass is pressed, and the liquid part is separated from the solid mass. The fixed mass is the sake kasu which is widely used in Japanese cuisine.
After this brewing process you have pure sake called junmai namazake. This is pure unpasteurized, unfiltered and undiluted sake. However, there are still some optional steps:
- Carbon filtering: the solid mass is already separated from the liquid sake. However, there is often another filter step added called Roka filtration or carbon filtration. This can be done in several ways but most common is by pouring powdered activated charcoal into the sake before it is fed through a filter. The result of this type of filtering is clear sake without excess taste or discoloration. The amount of charcoal used depends on the type of sake that is made and the brewery. Unfiltered sake is indicated as muroka.
- Pasteurisation: when pasteurising, the sake is in most cases heated to 65°C for 30 minutes. This can be done both after filtering and or after the sake has been bottled. Pasteurized sake is usually slightly flatter in taste and remains more consistent in taste over time. Unpasteurized sake is referred to as nama.
- Diluting: a lot of sake is diluted with water at the end of the brewing process. This reduces the alcohol content. Undiluted sake is indicated as genshu.
- Ripening: sake is not just like wine intended to ripen for a long time. Still, it does happen sometimes. The ripening is done in a metal vessel, on a wooden vessel or in the bottle. In time, the sake becomes darker in colour and richer and fuller in taste. Matured sake is referred to as koshu.