Productions Process
The production of shochu can take anywhere between four months to one year to complete. The length of time needed to complete the production process is dependent on a variety of things things. For example, the amount of time it takes to prepare the first mash (moromi) is around 3 or 4 days for sweet potato (imo) shochu but when producing brown sugar (kokuto) shochu, this step lasts for nearly one month.
Each shochu producer has their own time-honored production method, some of which have been used for nearly half a century. Many producers however have begun to implement automated equipment throughout each step of the production process.
Koji Preparation
Koji (Aspergillus oryzae) is most commonly produced using rice, but can also be created with buckwheat (soba), sweet potato (imo), or barley (mugi), as part of a painstakingly complex process requiring attentive care and expertise.
Koji is used to overcome the lack of sugar and overabundance of starch found in the base material. Koji is added to the selected base ingredient and its mold goes to work, triggering sacchrification, which results in substantial conversion of starch to sugar (glucose).
Without this step, the production of alcohol would be impossible due to the inability of the raw materials to ferment when mixed with yeast.
There are four basic steps in the production of koji:
- Washing and steaming the material,
- Applying the tane-kin,
- Proliferation of spores, and
- Cooling.
First moromi
The next step is to create a moromi, or mash in English. Mash is used in the production of other distilled beverages like whisky and scotch just as it is used to make shochu. To produce shochu, the moromi is created after the koji mold has fully propagated, placed into a tank and then combined with water and shochu yeast. This step is essentially the first phase of fermentation, but is strictly limited to these three elements: koji, water, and yeast.
The moromi mixture is held in a special container for typically one week, or in the case of brown sugar shochu one month. Metal tanks made of stainless steel or
enameled iron are the most common holding devices because they are cost efficient in both construction and labor. A number of shochu producers make use of earthenware pots during the fermentation and moromi phases. The use of earthernware is often associated with producers of handmade shochu, and it allows for a softer flavored drink.
The containers used to create moromi are generally submerged in the ground with only a small portion of the container exposed. Having the containers partially submerged enables the makers to keep a constant temperature of 25°C – 30°C. As in the koji process, keeping the temperature constant is important during fermentation to maintain a high level of quality. Submerging the containers is also beneficial because of their sheer size: some are as big as six feet tall and five feet wide!
Second Moromi
The creation of the second moromi, second mash in English, is a defining moment in the production process of shochu. This is basically when the main ingredient enters the stage and becomes the star of the show. This raw material will define the type of shochu in production, be it sweet potato, buckwheat, barley, rice, et cetera. Once the main ingredient has been washed, steamed, cooled, and crushed; it is combined with water and the first moromi.
In creating the second moromi, the process of converting glucose to alcohol (fermentation) occurs for the second time.
As with the initial moromi, the glucose from the koji rice reacts with the yeast to cause fermentation. In the case of the second moromi, the starch from the main ingredient reacts with the remnants of the koji to produce glucose, which consequently triggers fermentation as it reacts with the yeast. The final result is alcohol. The alcohol is quite apparent at this stage and is very noticable in the factory.
In this stage , the contents are held in containers from anywhere between 8-14 days, depending on the producer. The production processes of the first and second moromi are essentially the same except the second moromi contains the base material. The contents are held in large containers made of either metal or earthenware. The producers strive to keep the moromi at a constant temperature--usually between 25°C – 30°C, and the contents are regularly stirred to ensure a thoroughly fermented mixture to be used in the next stage: distillation.
Distillation
Distillation is an important process behind the production of any fine spirit, be it vodka, rum, whisky, or shochu. Generally speaking, the objective of distillation is identical for each: extract the alcoholic properties from a fermented compound of water and other raw materials through the boiling and condensing of the compound. Naturally, each spirit employs a number of variations throughout the distillation process, thus yielding end products with unique qualities of flavor and aroma.
After the fermentation , the moromi has a very low alcohol content: somewhere between five and ten percent, and as a result it cannot be classified as a spirit. Aside from the low alcohol
content, the moromi also doesn’t taste particularly well, so it is left to the distillation process to piece things together.
Additionally, distillation has a profound effect on the flavor and aroma of shochu. Each distillation method achieves a different result. This lends to the notion that any variations made in the production process can lead to completely different outcomes in flavor and aroma. For example, many producers of artisan shochu use a wooden still as oppose to the mass producers who use industrial sized, stainless steel stills. Some producers even adjust the angle at which the still sits in order to create a unique flavor.
Distillation is truly a turning point in the production of shochu in a number of ways. For starters, the distillation method provides a means for classification. In the world of shochu, the spirit can be placed into one of two categories: Honkaku (also known as Otsurui) or Kourui. Shochu that is classified as Honkaku is the product of a single distillation method. On the other hand, Kourui shochu production employs a continuous distillation method.
Shochu maturation can last anywhere from one month to a year depending on the producer and the base material of the product. For shochu, aging is necessary to rid the unpleasant odor and taste of gases caused by distillation. This venting of the gases also reduces the overall alochol content of the shochu, in some cases down to 30% alcohol.
Maturation
If there is one thing that distinguishes spirits, it is aging and maturation. For spirits like sherry, brandy and even whisky, it is an integral step in the production process because it creates a smoother, more flavorful beverage. White spirits (vodka and gin) on the other hand, skip this step all together and go straight from distillation to bottling.
When it comes to shochu, maturing plays a significant role, as it allows for another opportunity to further handcraft a shochu's characteristics. Nearly all aged distilled spirits exclusively use wooden barrels. Shochu, however, can be aged one of three ways: earthenware aging, metal tank aging, or wooden cask aging. Each adds unique flavor and aromatic properties that can only be attained through the implementation of aging.
Blending
Before bottling can take place, shochu must be blended in at least one of two ways: with water or with another shochu. Blending is basically a form of quality control each producer employs to ensure the customer receives the very best.
The idea of blending two post-production shochus together may sound a bit peculiar, but it is done with good reason. Each production cycle creates a product that is of similar--but different--characteristics. Therefore, to ensure consistency, the producer will mix newly produced shochu with remaining shochu from past production cycles in order to achieve a balance of flavor and aroma that can be easily duplicated.
Even after maturation, the alcohol content of shochu is above the typical 25% and 30% that most producers prefer. Therefore, makers must use water to dilute their product prior to bottling. The water mixed with the shochu generally originates from a pure and natural water source to guarantee no unwanted chemicals are added. Nearly all shochu on the market is mixed with water at the distillery. Recently, many producers have begun to bottle and sell this water for the hardcore shochu fans, who believe that using this water for their own personal cold water mix will create a beverage that is of the utmost quality and flavor.
Bottling and Labeling
The final stage of production is bottling: the least complex stage of the entire process. As in the production of other alcoholic beverages, the bottling process of shochu is fully automated and hands free. The producers also employ a form a quality control to ensure no unwanted material has found its way into the bottles.
In most cases, after a bottle has been filled, it is moved along a series of conveyor belts to a labeling machine. However, there are still producers who
choose to label all of their bottles by hand. One producer says the company chooses to hand-label their bottles because the labeling machines can not replicate the same aesthetic appeal as hand-labeling. Once the label has been applied, the shochu is ready for distribution.