JSA Part II

Genryo shori involves the processing of raw ingredients, specifically washing, soaking, and steaming the rice to prepare it for fermentation.

Koji, made from 20% of steamed rice, is essential for converting starches into sugars, which yeast can then ferment into alcohol.

Shubo is a starter culture that consists of 7% of the total steamed rice volume, including koji, and is crucial for cultivating yeast for fermentation.

Joso is the pressing stage where the moromi is pressed to separate the sake from the sake kasu, resulting in the final sake product.

Washing rice removes rice bran and initiates water absorption, which is critical for proper steaming and koji-making.

Drier rice absorbs more water; for example, 1% lower pre-soak water content can lead to a 3% higher absorption rate, impacting the quality of the koji.

Gentei Kyusui refers to limited water absorption for Ginjo-shu, where soaking time is restricted to about 10 minutes to prevent over-absorption, as Ginjo rice is drier and more brittle.

The primary goal of Jo-kyo steaming is to pre-gelatinize starch in soaked rice, making it more reactive to koji enzymes and increasing its solubility for fermentation.

• Firm outside, soft inside (gaiko-nainan).
• Fully gelatinized (no hard core).
• Not sticky on the surface.

• Untreated rice starch has tightly packed glucose chains, preventing enzyme penetration.
• After steaming, glucose chains separate and expand, creating space for enzyme action, which is essential for sake fermentation.

• Wagama (Cauldron): Made of heat-resistant bricks, heated from below by a burner, filled with water before heating.
• Koshiki (Steamer): Wooden or metal tub placed on top of the wagama, with a bottom hole for steam passage, and a koma for even steam distribution.

1. Preparation: Koshiki lined with cloth, filled with soaked and drained rice, separated by steam cloth.

2. Loading Rice: Rice added gradually to ensure even steaming, allowing steam to escape properly.

3. Steaming Time: Approximately 60 minutes total steaming time.

• Efficiency: Fully automated with no manual handling of rice.
• Continuous Process: Allows for uninterrupted steaming, enhancing productivity.

1. Natural Cooling:

   • Used for ginjo-shu.
   • Slower, gentler process.

2. Forced Cooling (Machine):

   • Uses a continuous cooling device with adjustable conveyor belt speed.
   • Cooling mechanism: Forced air draft while rice moves on a metal mesh belt.
   • Crusher Warning: A rotating cross-shaped metal bar—keep hands clear!

1. Induction Phase:

   • Begin to reproduce.

2. Logarithmic Growing Phase:

   • Double-up.
   • Produce alcohol & CO2.

3. Stationary Phase:

   • Slow down growth.
   • Alcohol concentration gets higher.

4. Death Phase:

   • Lack of nutrients.
   • Rise in alcohol concentration.

• Sake Yeasts:

  • Active in low temperatures (8-17°C).
  • Die at high temperatures.

• Bacteria:

  • Survive at different pH levels.
  • Lactic acid bacteria resist acidic environments but not more than pH 3.5.

1. Koji-rice: Highest temperature (for koji making).
2. Shubo (starter mash): Slightly lower temperature.
3. Moromi (main fermentation):
   • Hatsuzoe (1st stage): Cooler than shubo.
   • Tomezoe (final stage): Lowest temperature.

Yeast thrive the most at pH 4.0 - pH 5.0 and can survive at up to pH 3. In contrast, fungus thrives at pH 5.0 - pH 6.5 but cannot grow without oxygen in Moromi.

The four major enzymes in yellow koji are:

On Day 1 of Seikiku, the following steps are performed:

1. Hiki-komi (Bring in): Steamed rice at 36°C is brought in and laid onto the toko. Clumps are broken down and spread evenly at 35°C.

2. Tane-kiri (Apply tane koji): Tane koji is sprinkled over from a height of at least 50cm.

3. Toko-momi (Even out spores): The steamed rice is mixed thoroughly, wrapped with cloth to avoid drying, and piled into a hemispherical or mattress-like shape. The absorption rate is 32% for Ginjo and 33% for ordinary sake. Cells divide and hyphae grow after a few hours.

During Day 2 of Seikiku, the temperature controls for enzyme growth are as follows:

• Carboxypeptidase: Optimal growth at 35°C
• Glucoamylase: Optimal growth at 40-43°C
• Growth stops around 45°C

The 'Shimai-shigoto' stage occurs 6-7 hours after 'naka-shigoto' and is significant because:

• The temperature reaches 38-39°C.
• Haze-mawari (fungal spread) is about 70%.
• Distinct chestnut flower aromas (Kurika) develop.
• The mixture is spread over to a thickness of 4-5 cm and reaches peak temperature of 40-43°C, maintaining this temperature without additional work.

De-koji involves sending out koji and determining the timing based on sweetness and haze. It is traditionally checked by kurika and currently assessed by appearance, tracing night board, and microscope. Ordinary sake is produced sooner than ginjo-shu.

Sokujo-Shubo is a quick fermenting shubo that safely grows high-quality yeast by adding prescribed lactic acid. It retains an acidic environment to prevent unwanted microorganisms, operates at a high temperature of 18-20°C for quick decomposition and saccharification, and must be consumed within 7 days after cooling down to preserve newly formed yeast.

During De-zukai, adding koji to the moromi lowers acidity by 0.2, enhances fresh aroma, results in a lighter and less rough taste, and helps avoid hineta (aged koji with formed spores). Additionally, drying has a bactericidal effect, preventing ambient yeasts and unwanted bacteria.

Shubo Shitsu requires a dry, clean, and ventilated environment with a temperature of 4-5°C. It is essential to keep the shubo under 10°C during this stage to eliminate unwanted microorganisms and reproduce sake yeast.

Shikomi is the process of mixing cooled steam rice into mizo-koji, which is crucial for the fermentation process. It involves the use of lactic acid, pure yeast, and koji mixed into kumi-mizu, requiring more than 1 ampoule of kyokai yeast for every 100kg of rice used in shubo.

Lactic acid is essential for creating the right amount of acidity in the shubo, maintaining the acidity of the moromi, and preventing the growth of unwanted microorganisms during fermentation.

The following table summarizes the differences in koji rice and water use between ordinary sake and ginjo sake:

During the Fukure stage, the temperature increases to 15°C, which leads to the emission of a rich aroma and the activation of yeast. This stage is crucial as it marks the beginning of active yeast fermentation, with the overall temperature gradually increasing to reach waki-tsuki in one day.

In the Waki-tsuki phase, yeast production and fermentation accelerate, resulting in the release of carbon dioxide that creates bubbles. The Baume degree declines by one, and the Shubo temperature is raised by 2-3°C using daki to facilitate yeast growth, with the temperature around 17°C.

During the Waki-Tsuki Yasumi stage, yeast production peaks without the use of daki, as heat is generated by the yeasts themselves. Bubbles cover the entire surface, and there is a notable increase in aroma, acidity, bitterness, and astringency. The temperature ranges between 20-22°C.

The Wake (split) process involves lowering the temperature to ensure yeast survival. This is achieved by dividing the mixture using hangiri. The temperature during this stage is between 20-23°C, leading to a decrease in sweetness and a slight dry taste, along with clear acidity and astringency.

Ko-on-toka-shubo is used to shorten the lead time for saccharification and enzyme activation. It involves quickly decomposing and saccharifying steamed rice at a higher temperature, where koji enzymes are most active at 55°C. This process takes about one week and is crucial for preventing unwanted microorganism growth while promoting desired fermentation.

Kimoto, which started in the early Edo period, and Yamahai, which began in the Meiji period, both focus on culturing lactic acid bacteria to prevent contamination. However, Kimoto is mashed at 5-9°C, while Yamahai allows for a slightly higher temperature, promoting the survival of good lactic acid bacteria at around 7°C and preventing the growth of bad bacteria that thrive at 10°C or higher.

Kyokai kobo is a trademarked yeast distributed by the Brewing Society of Japan, playing a crucial role in sake fermentation and quality.

The Daki-ire process is used to accelerate saccharification and promote lactic acid production. It involves raising the temperature by 1°C per day for 2-3 hours at a time, which enhances the activity of enzymes and supports the fermentation process.

The Karashi period lasts 1-2 weeks and is crucial for enhancing the fermentation strength of the yeast.

The San-Dan Jikomi method consists of the following steps:

1. Hatsu-zoe: Shubo, water, koji, and steamed rice are added; target temperature is relatively high to focus on yeast growth.
2. Odori: Yeast reproduces without any additions.
3. Naka-zoe: Water, koji, and steamed rice are added again.
4. Tome-zoe: Water, koji, and steamed rice are added to slow down yeast activity and reduce spoilage risk due to lactic acid bacteria.

Lactic acid bacteria are promoted by nutrients that melt out from cooked rice, which helps in the fermentation process. They coexist with nitrous acid and lactic acid, and their gradual die-off is followed by the decline of lactic acid bacteria.

The Akita Style Kimoto, created by Kenkichi Kodama, uses an electric mixer instead of a hangiri and employs higher mashing temperatures (14-15°C) to accelerate decomposition and saccharification. It also utilizes so-haze to avoid haya-waki and an electric heater (anka) to prevent unwanted microorganisms.

Bodai-moto was used in the 15th century, involving 10% cooked rice buried in 90% raw rice, promoting lactic acid bacteria growth. It was established by Shoryaku-ji and was part of a single-stage brewing process called bodai-sen, where temples brewed sake as offerings to deities.

Mizu-koji involves mixing cold water (3-5°C) with koji for 2-4 hours before mashing, allowing enzymes to seep into the water, which is essential for the fermentation process.

Potassium nitrate is added (5-10g/100L water) to avoid haya-waki, which is excessive yeast growth, thus maintaining a balanced fermentation environment.

The modern Kimoto and Yamahai methods, developed during the Meiji period, have reduced the workload of yama-oroshi and are now widely appreciated. Current production shares are 90% sukujo, 9% yamahai, and 1% kimoto, utilizing stainless steel hangiri and doki-daru with no regulations on grind time or tools.

The surface begins to crack and sujiwa appear, indicating that fermentation is proceeding smoothly. The semi-solid moromi will gradually decompose and become thinner as alcohol emerges.

Heiko-fukushiki-hakko refers to multiple parallel fermentation where saccharification of steamed rice occurs simultaneously with sugar breakdown by yeast, although they do not proceed at the same speed.

The time required to make moromi is primarily dependent on temperature. For Honjozo & Ordinary sake, it takes 20-25 days at specific temperature ranges, while Ginjo takes 4-5 weeks with a gradual temperature increase.

Gen-ekisu is an index that indicates how far the steamed rice in the mash has decomposed, expressed in terms of concentration%. It reflects the decomposition speed of steamed rice during fermentation.

1. Prohibiting outside shoes indoors and ensuring cleanliness of tools and tanks.
2. Mashing with low pH shubo and adding large amounts of pure yeast to limit lactic acid bacteria growth.
3. Avoiding sudden dilution of yeast cells and maintaining low fermentation temperatures to inhibit lactic acid bacteria growth.

Kumi-mizu-buai, the ratio of water to total rice weight, dictates the fermentation speed of moromi. Increasing kumi-mizu-buai accelerates fermentation and increases heat generation.

Shubo-buai, the ratio of rice used for shubo making to the total weight of rice used for moromi, increases fermentation speed when it is higher. Ordinary sake has a shubo-buai of 7-8%, while ginjo has 5-6%.

Koji-buai refers to the ratio of koji-rice to the total rice weight used after shubo making. Increasing koji-buai enhances yeast cell production, leading to increased acidity in moromi and richer flavors. A typical koji-buai is around 21%, with a normal range of 20-23%. Conversely, decreasing koji-buai results in a light, flat taste.

Yodan Wariai is the fourth stage of mashing where steamed rice is saccharified at 55°C using enzyme agents and added to the moromi. It typically comprises 4-10% of the total rice in moromi and is used to add sweetness and depth, commonly found in honjozo and ordinary sake, as well as some junmai.

Joso is the process of pressing moromi to separate it into sake and sake-kasu. The pressed liquid, known as sei-shu (clear sake), is obtained through this process, which is referred to as kosu (filtering) under the Liquor Tax Act. The pressing involves using a fune, a large rectangular structure, where moromi-filled saka-bukuro bags are layered and pressed.

The Joso process yields three main fractions:

1. Arabashiri - the first pressed, youthful with a clean taste.
2. Nakadori / Nakakumi - the main fraction.
3. Seme / Oshikiri - the final fraction pressed with high pressure, which may have undesirable qualities if not handled properly.

The Automated Pressing Machine resembles a large accordion and consists of multiple filtration units made of filter cloth and pressing plates. It applies pressure through air in a sealed condition, allowing for efficient separation of sake from moromi while maintaining quality.

Shizuku-Shibori is a drip pressing method where saka-bukuro filled with moromi are hung from bamboo bars, allowing sake to drip by its own weight. This method results in clearer and higher quality sake, often used for competitions. The first pressed sake tends to be murky and rough, while subsequent bottles become more mature and flavorful.

Nigori-zake is a type of cloudy sake produced through rough filtering of moromi using a stainless steel colander-like mesh, resulting in a murky appearance that contains yeast. Variants include Momo-iro-nigorizake, which uses pink-colored yeast, and Kassei-seishu, a sparkling cloudy sake that has not been pasteurized.

During the bottling process, sake is pasteurized and packaged. The thermal insulation effect of cardboard and the stacking of boxes can lead to aging of the bottled products. Techniques include packing products in boxes the next day, stacking in various ways to create gaps, and using perforated cardboard boxes to ensure proper cooling and preservation.

Brewer's alcohol, known as aruten or aruten-shu, is fermented and distilled from starch and saccharides. In the mid-1950s, it was primarily made from imported waste molasses, which was fermented in Japan and distilled until reaching about 95% alcohol content. By the 1970s, the production shifted to using foreign crude alcohol, which was distilled further in Japan. Recent years have seen a return to using waste molasses, molasses, sweet potatoes, and corn as raw materials.

Adding brewer's alcohol enhances the aroma and clarity of the sake. It also prevents the growth of lactic acid bacteria (hiochi-kin). However, after the war, due to rice shortages, the government encouraged the production of triple brewed sake (san-zo-shu), which contributed to a negative perception of alcohol-added sake. The amount of brewer's alcohol allowed in specially designated sake is capped at 10% of the total white rice volume, with most cases using less than half of that limit.

Genshu is a type of seishu (refined sake) that is not diluted after brewing to adjust its alcohol content. While unprocessed sake typically has an alcohol content of about 20%, water (wari-mizu) is usually added to achieve 15-16% alcohol content. Genshu allows for minor adjustments of up to 1% alcohol content between batches without dilution.

Hi-ire is a pasteurization process used to halt residual enzyme activity and eliminate hiochi-kin and other bacteria. It typically occurs at temperatures of 60-65°C and is performed twice: after pressing and after bottling. Common methods include the coil type (jakan-shiki) method, where sake is passed through boiling water, and the plate-type heat exchanger, which uses alternating plates for heating. Binkan hi-ire involves pasteurizing bottled sake by dipping it in hot water.

Ori-biki is a process that occurs after pressing sake, where the dregs (starch, insoluble proteins, yeast, etc.) settle at the bottom of a tank set at low temperature. After a few days, the clear sake is drawn from the top drainage hole (uwa-nomi) to avoid sediment. Sake taken from the lower drainage hole or bottled directly without ori-biki is referred to as ori-garami or ori-zake.

Dried yeast #701 and #901 eliminate the need for shobu, resulting in:

• Shorter brewing time
• Less manpower
• Reduced cost

The objective of brewing jizake is to use local rice, water, and yeast of local origin to create unique regional sake.

The first yeast successfully extracted from moromi in 1895 was announced as 'Saccharomyces sake Yabe' in 1897, named after Professor Kikuji Yabe, marking a significant advancement in sake fermentation science.

Traditional Kyokai Yeast #7, extracted in 1946 from Masumi in Nagano, is known as Masumi Yeast. It became the standard yeast after World War II and is recognized as a best seller due to its reliable fermentation properties.

Modern Kyokai Kobo #1801, distributed in 2006, is characterized by high acetic acid and ethyl caproate, low acidity, and high power, making it distinct from other yeasts that may have different acid profiles or power levels.

Traditional Kyokai Yeast #12 was extracted in 1965 from Urakasumi in Miyagi and is known as Miyagi Kobo. It is a low-temperature Yamahai yeast but is currently not distributed.

Modern Kyokai Kobo #1601 is characterized by low acidity and high ethyl caproate, which contributes to its unique flavor profile in sake production.