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What is Sake?
Ingredients
It takes four ingredients to make sake: rice, water, yeast and koji. This seems fairly straightforward but appearances can be deceiving. Special rice, sakamai called, is used to make sake and is prepared by polishing to a greater or lesser extent. The quality of the water also varies within each region. The dissolved minerals greatly influence the flavor and fermentation of the sake. Yeast is another ingredient that contributes to the flavor components of sake. Individual breweries and regions develop their own yeast strains. The fourth ingredient - koji - is the fungus spread over the rice to convert the starch into sugar. Again, different varieties of koji are used. Together with the brewing process, and the choices made in it, this determines the unique flavor profile of each sake.
Rice wine
Sake is often called “rice wine” because, like wine, it contains unique variations of flavors with subtle aromas. In addition, it is often drunk like 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 to sugar and sugar to alcohol simultaneously (not sequentially as in beer).
Brewing Process
Brewing sake requires experienced brew masters to master 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 - play into the flavor, aroma and final outcome.
Briefly, the sake brewing process boils down to the following steps.
- Polishing: To remove impurities such as grease and proteins, rice is first polished.
- Washing and soaking: The remaining rice cores are then washed and soaked.
- Steam: After soaking, the rice is steamed.
- Koji: After steaming, part of the rice is sprinkled with koji. This noble fungus penetrates 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 here, the generation or addition of lactic acid creates the optimal conditions for the yeast cells to do their job of transforming sugar into alcohol. The longer this process the more complex the flavor.
- Scaling up: in several stages, water and even more rice are then added. This creates the final brewing mass. What is unique about sake is that the formation of sugar and alcohol occur simultaneously in this mass. This is also the reason why sake contains the highest percentage of alcohol of all alcoholic beverages, solely through fermentation.
- Press: After about a month, the mass is pressed and the liquid portion is separated from the solid mass. The solid mass is the sakekasu which is frequently used in Japanese cuisine.
Optional steps
After this brewing process, you have enjoined pure sake junmai namazake. Or while pure unpasteurized, unfiltered and undiluted sake. However, there are some optional steps:
- Carbon filtering: the solid residue is already separated from the liquid sake. However, another filtering step is often added called Roka filtration or carbon filtration. This can be done in several ways but most common is by pouring powdered activated carbon into the sake before passing it through a filter. The result of this type of filtration is clear sake without excess flavor or discoloration. The amount of charcoal used depends on the type of sake being made and the brewery. Unfiltered sake is referred to as muroka
- Pasteurizing: Pasteurization involves heating the sake to 65°C for 30 minutes in most cases. This can be done after filtering and or after the sake has been bottled. Pasteurized sake is generally slightly flatter in taste and also remains more consistent in taste over time. Unpasteurized sake is referred to as nama.
- Dilute: a lot of sake is diluted with water at the end of the brewing process. This reduces the alcohol content. Undiluted sake is referred to as genshu
- Ripening: sake, like wine, is not meant to age for a long time. Yet it sometimes does. Aging occurs in a metal vessel, on a wooden barrel or in the bottle. Over time, the sake becomes darker in color and richer and fuller in flavor. Aged sake is indicated by koshu.