Sake is an ancient beverage, produced for over 2,000 years in Japan. Despite this long history, the industry's lack of standardization often leads to conflicting definitions and confusion. Yet a focus on regionality, Jizake (microbreweries), and improved regulation are improving sake's worldwide reputation. Today, it is clear that there is a place for sake in a wide variety of beverage programs, well beyond Japanese restaurants.
Although it has a similar alcohol by volume to wine, sake isn’t made from grapes, and the process is not a single-step fermentation from sugar to alcohol, so it is technically incorrect to call it rice wine. Though brewed, sake isn’t like a beer, either. Rice doesn’t get malted the same way as barley, and sake often achieves a much higher potential alcohol by volume. Sake is entirely unique: in a single tank, starch converts to sugar and yeast consumes sugar to produce alcohol (and CO2) simultaneously in what is called multiple parallel fermentation.
Sake production has been passed down over centuries of practical application, blurring the lines of tradition and innovation. Today, technological advances and modernization have changed the industry. With at least one sake brewery (kura or sakagura) in each of Japan’s 47 prefectures, it is becoming harder for brewers to keep their secrets. While sake is often made with minimal intervention, breweries do have their techniques—and some are “cleaner” than others.
The number of sake breweries in Japan is a fraction of what it once was. There were upwards of 30,000 sake producers during the Meiji era (1868-1912), and after World War II, over 4,000 remained. Now, there are only about 1,500 breweries with licenses, with just three-quarters of them actively producing. Yet other modern changes have been enormously positive. In 2016, the World Trade Organization gave geographical indication (GI) status to two prefectures: the entire prefecture of Yamagata in the north (Yamagata GI) and the breweries Tengumai, Kikuhime, Tedorigawa, Manzairaku, and Takasago in the town of Hakusan in the centrally located Ishikawa Prefecture (Hakusan Kikusake GI). The Yamagata GI rules state that the 51 breweries of the prefecture must use rice and koji grown in Japan, use only Yamagata water, and bottle and store their sake in Yamagata. The sake must pass a panel judgment from the Yamagata Prefecture Sake Brewery Association, which will test the product and ensure it has an identifying “Silky and Clear Texture.”
One thing is certain: the world of sake has come a long way from its roots of doburoku, the rustic, unrefined homebrew sake made in millennia past.
Rice farming in China can be traced back approximately 10,000 years, and in Japan, about 4,000 years. Sake has become uniquely Japanese over the last 2,000 years or so. In Japan, the term sake (酒) refers to all alcohol. Theoretically, if you walked into a busy Japanese izakaya, or neighborhood pub, and ordered a sake, you might receive a draft beer rather than a glass of Japan’s fermented rice beverage. The word nihonshu (日本酒), meaning “Japanese alcohol,” is the most appropriate word for the nation’s national alcohol, although the term seishu (清酒), or “clear alcohol,” is often used for legal and taxation purposes.
The first imperial sake brewing department was established in Nara, Japan, in 689 AD. At that time, production was usually reserved for the budding nation’s imperial court, its temples, and its shrines—not unlike how churches in Europe were managing winemaking. In the 10th century, the legal book Enshiki was published, outlining an elemental but standardized sake-making process. By the 14th century, sake production was relatively commonplace. By the 16th century, a process not unlike pasteurization was being developed—long before the birth of Louis Pasteur in France.
The modernization that led to today's sake took place in the 20th century. Production advances such as integration, and then enforcing, of stainless steel or ceramic-lined tanks for fermentation and storage inhibited the bacterial growth and leakage associated with the cedar barrels most brewers had used. Other important developments included mechanized rice milling machines, genetically modified rice varieties, and new yeast strains.
In August of 1945, when atomic bombs were dropped on Nagasaki and Hiroshima, everything within a one-mile radius of the drop zones was destroyed. Originally, it was thought that it would take 70 years for the regions to rebuild, but just one month later, flowers began blooming within the blast radius. The Makurazaki Typhoon hit in September of that same year, bringing in radiation-free topsoil and diluting nuclear contents of the area, a ray of hope for the agricultural industry. But, of course, the typhoon also took a tremendous toll.
During this time, sake batches were stretched out by dilution with water and addition of a brewer’s spirit made from cheaper ingredients that fortified and thinned out the sake, a process that expanded output at the expense of flavor and balance. In 1943, to control production, the Japanese government introduced a sake class grading system that divided sake into three categories: Special Class (tokkyu), First Class (ikkyu), and Second Class (nikyu). By 1968, the first pure junmai-shu, a term whose characters translate as “pure rice alcohol,” were being produced by Chiyonosono from Kumamoto Prefecture—a full year before preservatives were legally banned in sake production.
In 1991, this system was converted into the Junmai System, which had more stringent control on everything from polishing rate to use of additives.
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High-quality sake is comprised of a maximum of five key ingredients: rice, water, yeast, koji mold, and brewer’s spirit (distilled alcohol). Within sake, there are two overarching official categories. One category, Junmai (“pure rice”) uses only the first four ingredients, with styles including Junmai, Junmai Ginjo, and Junmai Daiginjo. The other category, called Arukouru Tenka or Aruten, is sake with spirit added. It is comprised of all five ingredients, with styles including Honjozo, Ginjo, and Daiginjo. Where the brewer’s spirit was once used to dilute sake while fortifying it and masking impurities, today it is added for minerality and texture. Known as jozo-alcohol, it is normally made from distilled rice or sugar beet and is unaged, colorless, and often flavorless. It can be produced anywhere. Japan’s National Tax Agency states that the ABV of the jozo-alcohol itself cannot exceed 95% (usually diluted to 30%) and that its weight in the final product must not exceed 10% of the weight of polished rice.
Legally, producers can work with table rice varieties, but they are stickier and therefore more difficult to work with. Sake-approved rice varieties of the subspecies Japonica, on the other hand, are short- or medium-grained and tend to be spongy and dry rather than sticky, making them difficult to eat. Over 80 sakamai (sake rice) varieties are officially recognized for sake production in Japan. These varieties tend to be heavier and about a quarter taller than table rice, or kakomai. With a spongier texture, sakamai has a unique ratio of fat and protein on the outside, with a particularly starchy center concentrated on the inside. This white heart, or shinpaku, is key to sake production.
Cultivating sake rice is more challenging than growing table rice due to wind and top-heavy crops. Table rice tends to be less top heavy, less prone to wind damage, and easier to work with throughout the growing process. As a result, sake rice is more expensive than table rice. The Japanese Government controls the area of land under rice paddy to avoid surplus.
Sake ferments to about 8 to 20% natural alcohol. However, to avoid additional taxes, the final product is often diluted to around 15%. Legally, sake must have an alcoholic content of no more than 22% ABV.
A sake label can never have a vague indication of high quality. For example, ichiban and daihyo, “number one” and “leading,” respectively, are not permitted on labels.
Rice shines in its ability to perform as a vehicle for the other ingredients of sake production, playing a role that is highly intricate—though perhaps less obvious than the one grapes play in winemaking. A sake producer will place high value on a variety of sake rice that can absorb the right amount of moisture, cooperate with and be penetrated by koji mold, and interact with various types of yeast. These traits are generally more important than the actual flavor of the rice. It’s not uncommon for producers to pay upwards of three times the price of table rice on high quality sake rice.
While some producers grow their own rice, they usually don’t grow enough to sustain their entire sake production, so they work with farmers and cooperatives. Producers typically contract a rice paddy and have it managed by experienced farmers. Rice paddies are small, flooded fields of arable soil used for semiaquatic rice cultivation. Paddies are surrounded by impermeable subsoil that forms a border, and they are typically flooded with 10 to 15 centimeters of water. Growing rice requires a significant amount of water, so the water-retaining soils of silt, clay, and loam are preferable when establishing a rice paddy.
In sake rice cultivation, pesticides are rare and sustainable methods common. Certification for organically produced sake is tied to agriculture, not methods employed inside the brewery. Certified organic sake must come from a rice paddy that has been free from synthetic products for a minimum of three years.
Planting can start as early as April or as late as June, and it begins with taking seeds from the previous year. Rice paddies are primed with water and tilled soil to create an environment that welcomes infant seedlings, or nae, but inhibits the growth of nutrient-sapping weeds.
Sake rice likes strong diurnal shifts, with hot days and cold nights. These temperature changes cause starch from the outside of a grain of rice to be collected into its center to make a good shinpaku with a high concentration of starch. Rice also loves sunlight. In years with lower average temperatures and less sunlight, the grains are smaller and more soluble, resulting in a rounder, more definitive rice flavor. This will also result in a lower kasubuai, a term referring to the percentage ratio of sake kasu (pomace left over after production) to the original volume of polished rice used to create the sake. In hot years with more sunlight, the starch becomes less soluble at its shinpaku. The resulting sake will be leaner, with a higher kasubuai.
After flowering and self-pollination, the rice grains (ine) begin to appear from the center of the stalk. As these grains get plump, they slouch down from the main plant, and once mature, they are harvested. Harvest begins in autumn. Cold temperatures threaten the crop, as the water in the grains and stalks of rice and even the rice paddy itself can freeze. In the north of Japan, rice is harvested starting in early September; harvest is significantly later in the south. On the southern island of Kyushu, it begins as late as mid-October. These varying temperatures and harvest dates contribute to the typically leaner northern styles versus the richer and mellower styles of the south. The north generally uses the current year’s rice, but in southern Japan, producers often use rice stored from the previous year in cool, temperature-controlled conditions. For small breweries, this can be a challenge, as many cannot afford storage and temperature control; they frequently import rice from further north to keep up.
Weeds are a primary concern throughout the growing season. They can sprout at any time, including during the draining of the rice paddy and at harvest. Steps are taken to minimize damage of the paddies, but weeds can also be taken in by the harvest machine. As a result, in potentially troublesome areas of the paddy, hand harvesting may be necessary. Another concern is the overgrowth of rice stalks. If rice is too well nourished, the ears become very heavy, and the stalks may buckle under their weight. Also, taller stalks are prone to wind damage, so growers don’t want too vertical of a growth.
After harvest, the grains of rice are stripped from the ears and separated into different hoppers. It is important that the rice grains are dried quickly to avoid rot. The warming process brings their moisture content down to 14 to 15%, preserving them for later use. This moisture content is regulated by the government, as rice is sold by weight.
Underdeveloped or fragmented grains are removed, and the remaining, approved rice is separated by size into different categories, all of which can be found in a single paddy. There are five grades of size for classifying rice: Santoh (Grade 3), Nittoh (Grade 2), Ittoh (Grade 1), Tokuto (Special Grade), Tokujo (Higher Special Grade). Tokutei meisho-shu, meaning “special designation” or “premium” sake, must be made from rice that has been given one of these five grades. This is the high quality sake typically seen in restaurants; it makes up about 26% of all sake produced in Japan. Along with following the guidelines for rice size, sake at this level cannot have any preservatives, coloring agents, flavors, or fragrances added during or after production, a regulation enforced by law.
Once the rice stalks are chopped, some fields are burned and others left to decompose. With the former method, farmers can make good fertilizer from the ashes; the latter requires minimal intervention in the paddy until the following growing season.
The production cycle of sake takes roughly a year. Rice is planted in the spring and ready for sale by the end of autumn. In winter, the sake-making process begins.
After being harvested, prepared, and sold, sake rice is milled using a machine called a seimaiki. Housed in a large building, it operates 24 hours a day, staffed by three kurabito, or brewery workers, on rotating shifts. Most breweries do not have their own milling machines, so they will use offsite machines. Breweries that do have machines will sometimes provide milling services to smaller breweries.
Sake was once washed rigorously through wicker baskets, and only when a grain of rice was small enough would it fall through the calibrated hole of the basket. Some producers still use that method, but the labor and expertise required make it largely impractical. Milling machines appeared in Japan in the early 1930s. A horizontal machine is typically used for table rice, and a gentler vertical machine is used for sake rice. The size of the machine is indicated by the size of the millstone, which ranges from 40 to 65 centimeters.
The milling process, called seimai, begins with brown rice (genmai). Inside the machine, the dry rice grains are slowly milled in a polishing chamber with a roll made from an extremely hard material, then fall vertically through the mill. The machine removes the outer layers, at which point the rice is considered hakumai, or white rice. Further polishing gently removes the fat and protein outer layers of the hakumai, contributors to rustic, fatty, and earthy flavors. Once the polished rice grains leave the chamber, a series of perforated plates separate the resulting flour (nuka) and the adequately polished grains. A calibrated hole will reject rice that is insufficiently polished, moving it back to the top with a bucket conveyer to go through the process again. The nuka will be used for cattle feed, fertilizer, rice crackers, and more.
Controls such as the aperture of the hole that accepts the polished rice and the revolutions per minute of the machine are closely monitored. If the rice gets too hot or dry during the process, it will be useless.
The term seimaibuai refers to the amount of rice that remains after polishing. For example, if a sake has a seimaibuai of 68%, 32% of the outer fat and protein has been polished away, with 68% left. The more a grain of rice is polished, the longer the process, the greater the risk of damage, and the more rice that will be required for the final product. It takes 50 hours to polish a grain of rice to 50% of its original size (seimaibuai 50%) and 50 more to remove another 15% (seimaibuai 35%). While sake rice can reach experimental seimaibuai of levels as low as 6%, this is rare, and the difference the extra polishing makes is questionable.
One producer from Miyagi in northern Japan, Hakurakusei, uses a rice polishing machine whose milling roll is made with diamond crystals and purportedly cost three million USD. Using the ultra-hard diamond surface, they released their Super 7 Junmai Daiginjo with a seimaibuai of 7%. This release, with several variations, is the most widely available bottle made with highly polished rice. Yet even this is extremely rare, and bottles are very expensive.
Typically, lower seimaibuai (more fat and protein removed) leads to more elegance, delicate flavors, and vibrant aromatics, while a higher seimaibuai (less fat and protein removed) produces more rustic and savory styles of sake. Later, a producer will decide to add brewer’s alcohol if more texture, body, and minerality are desired; this can also soften any overwhelming aromatic components and flavors.
Sake can be divided into several categories, displayed on this chart and outlined below. The suffix -shu (酒) translates as “alcohol” and is often left off. For all intents and purposes, Junmai-shu is the same as Junmai. It is also important to note that the polishing percentages are minimums, and a brewery may polish beyond the minimum. For example, a no-alcohol-added sake with a seimaibuai of 60% could be classified as Junmai Ginjo or Junmai; it's up to the brewer.
This lower category comprises roughly 75% of all sake produced in Japan. It has no seimaibuai rules, and additives are less prohibited. As the category has simpler tax legislation, there are a few microbreweries, such as Ibaraki Shuzo in Hyogo Prefecture, who take advantage of the less stringent rules to add some unique declassified craft sake to their lineup, but these instances are rare. Consumption of this category, especially outside of Japan, is falling drastically, while small craft breweries’ sales are going up exponentially each year.
This type of sake is brewed using a small amount of distilled pure alcohol to add texture and lighten the sake. This was originally a way to compensate for the shortage of rice after World War II. Today, the addition of alcohol doesn’t necessarily lessen sake’s quality; rather, it changes sake’s characteristics and often creates a more mineral-driven, cleaner beverage.
The seimaibuai of Junmai must be stated on the label, but by law, there is no minimum. Seimaibuai of 70% or less is typical. This sake is usually more robust, structured, and umami driven; it is often referred to as aji (flavorful). The sake is made with nothing but rice, water, yeast, and koji mold (i.e., no brewer’s spirit).
To be classified as Tokubetsu Junmai, sake must be polished to at least 60% seimaibuai or somehow diverge from the producer’s usual methods. If the latter, this distinguishing characteristic must be stated on the label. For the example, if a Junmai is produced by the traditional Kimoto method (described in the yeast section below) and this is outside of the brewery’s usual style, as long as this is noted on the label, the sake’s seimaibuai could be 70% and the bottle still labeled as Tokubetsu Junmai.
This sake, with a seimaibuai of 60% or less, is the perfect harmony of kaori (aromatic, fruity, floral style) and aji (textured, savory, taste-driven style). When spirit is added, the sake loses its Junmai prefix.
Often a kura’s most coveted sake, this style must have a seimaibuai of 50% or less. Some Daiginjo are polished so much that only 9% of the original rice grain remains—these examples tend to be delicate and vibrant, with many exotic fruit and floral characteristics. They are often referred to as kaori. When spirit is added, the sake loses its Junmai prefix, and the final product gains roundness and texture by way of viscosity from the brewer’s spirit.
In the following steps of the process, the role of toji, or brewmaster, is an important one. Toji study at toji shudan or ryuha (“schools” or “guilds,” respectively), of which there are 26 today. Created at the end of the 18th century, the toji guilds have become a center for identity and knowledge for sake-producing regions. Most toji will study near their hometowns to take on the unique local approach. They study both through text and hours logged producing sake. Studying is a job taken extremely seriously. Multiple guilds can exist in the same prefecture. Three of note are Echigo Toji (in Niigata), Nanbu Toji (in Iwate), and Tanba Toji (in Hyogo). The guilds long predate current political boundaries, and loyalty to them remains fierce. However, the exchange of information is becoming more open, and the guilds’ relevance is not what it was in feudal Japan.
Once rice has been milled, it is left for about two weeks to rest and absorb ambient moisture. One reason that sake is produced in the winter is because, even today, producers are usually located in large buildings without internal cooling systems. Cool winter temperatures ensure a long and healthy fermentation, resulting in a balanced and clean sake. Working in warmer temperatures would require air conditioning.
Early in the morning, rice is washed and soaked to absorb water. The rice is packed in 10-kilogram batches in mesh bags, soaked for approximately 30-second intervals, and weighed after each soaking to track how much moisture has been absorbed. The temperature of the water and rice must match to avoid cracking of the rice grain. The rate of soaking will affect the way the rice cooks when steaming, and ultimately the way the koji mold interacts with the steamed rice. The volume of the water-soaked rice is brought to about 30% more than its initial weight. There is always variation, however, and each brewery has its own proprietary method.
Once soaked, the rice is steamed for roughly 45 to 60 minutes to break up the starch molecules and sterilize the rice. Adding an additional 12% moisture to each grain of rice, the goal of the process is to make the rice hard on the outside and soft on the inside, encouraging the koji mold to work toward the moist, starchy center once it is introduced.
After steaming and a cooling period called karashi kikan, batches are separated for their intended purpose. Most will be used for the day’s yeast starter, which is known as moto or shubo, and the rest (ranging from 20 to 40%) will be moved to the koji room, or koji muro. To create the best environment for bacteria growth, the rice for koji propagation needs to be more gently cooked than the normal rice used in sake production, so the kakemai (non-koji rice) is always at the bottom of the steaming tank while the kojimai (rice that will be sprinkled with koji mold) is at the top for a gentler steam.
It is in the koji muro that the starches locked up in the middle of the grains of sake rice are converted to sugars. In this room, usually resembling a sauna lined with wood or metal (the latter is arguably more sanitary), the rice is spread out on a large table and koji mold spores are delicately sprinkled over top in an almost ritualistic fashion. Each brewery has a technique for this process, which has an impact on the success of each batch of sake. “Koji mold” is the name of the product sprinkled on the rice, and the resulting product is simply called “koji.”
Koji mold is found in ambient environments throughout Asia, and while it was discovered in China, Japan has championed it as their own spore and has dedicated research centers to its cultivation. There are less than 10 koji mold producers in Japan, but they all have an array of unique koji to offer. The koji chosen by the toji will affect everything from acidity to potential alcohol and aromatic potential. Factors considered in this decision include the type of rice that will be introduced to the koji mold, the pH of the water the brewery uses to steam the rice, and the temperature at which the koji mold will be introduced to the rice. To produce a single tank of sake, 100 grams of koji will be used.
Not just for sake production, koji is a catalyst for fermentation in other fermented products such as miso, soy sauce, and mirin. The koji used for sake production is usually yellow koji (Aspergillus Oryzae), while black and white koji are used for shochu production, and typically in warmer climates.
When sake is produced using non- or low-alcohol producing yeast, the resulting sweet, often fruity, congee-textured beverage is called amazake. Centuries old, it is a favorite served to kids and often praised for its health benefits.
The koji rests for about 24 hours and is then moved to a more precise temperature-control system of wooden trays and boxes for further propagation and mixing to maximize even distribution of the koji mold. After two days, it is moved out of the koji muro to stop the spread of the spore and prepare it for the yeast starter. The rice at this point looks like it has frosting on it (the koji mold) and has a sweet taste reminiscent of frosted flakes. While there are machines that can do this process, most quality producers do most or all their koji production by hand.
At this point, the koji and kakemai, at a ratio of roughly 25 kilograms koji to 37 kilograms kakemai, are combined in a tank with yeast and 80 liters of water. The seimaibuai of the steamed rice and koji do not have to be the same, but if they are different, this must be stated on the label. This mash will ferment until it has a high enough concentration of yeast cells to support further addition of rice and water (with a little help from some extra koji).
Here, lactic acid must be cultivated or added, a crucial step as it protects the fermentation from other, unwanted bacteria. The traditional method, used for centuries, is called the Kimoto method. Workers pound the mash with large wooden poles for hours at a time, cultivating naturally occurring lactic bacteria from the air. Natural nitrous bacteria exist in water and create a nitrous-reducing acid, which kills unwanted bacteria. Sphere-shaped lactic acid bacteria grow in that nutrient-deficient environment. The bacteria create lactic acid, which will kill itself. Next, bar-shaped lactic bacteria develop into a new lactic acid, which is more efficient and will survive longer. While all of this is happening, yeast is turning sugar into alcohol. At 10% ABV, the lactic bacteria cannot survive, so before this point, the moto will be transferred. The process results in a creamy, zesty characteristic.
In 1909, it was discovered that even without this bâtonnage, natural lactic acid could still form on top of the moto and protect the sake through its fermentation. The resulting flavors are more vibrant, gamier, and higher in both acid and fruit characteristics. This is the Yamahai method.
Another method was discovered in 1911, when producers found that lactic acid could be introduced, significantly shortening the process of creating the moto. This method, called the Sokujo method, grew in popularity; today, most sake is made this way. The Sokujo method is by far the most efficient, with moto production taking roughly two weeks. With the Yamahai and Kimoto methods, the process takes about one month. Sohomare in Tochigi Prefecture is one of the breweries credited for keeping the longer processes alive—and perhaps even making them trendy again.
There is one more method that predates the rest. Around the eighth century, the country was still honing its knowledge of sake production. A form of sake was made by Bodai monks for the temples, in which they mixed steamed rice with raw rice and water to encourage the natural production of lactic bacteria. Yeast could be added to this starter mash, initiating fermentation. This ancient method is called Bodaimoto.
After the addition or cultivation of lactic acid, koji, kakemai, and water will be added in three stages over the following six days in a process called sandan shikomi. The stages, in order, are known as hatsu-zoe, naka-zoe, and tome-zoe. Between the first and second stages comes odori: the “dancing ferment” where bubbles form as yeast interacts with sugar and starch is converted to sugar. Temperature, pH, sugar content, and alcohol are closely monitored and can be manipulated if necessary. One method for temperature control is to use jackets around the fermentation tank that contain running cold or hot water.
By the final day of preparing the shikomi (main fermentation mash), roughly 1,310 liters of water, 200 kilograms of koji, and 800 kilograms of rice will be fermenting. The mash will run for 20 to 30 days, meaning that, depending on the methods employed, it will take just over 30 to more than 60 days to make one batch of sake.
When the moto is ready, it is transferred into a larger tank by pump or by hand. Here, the main fermentation, or moromi, takes place. Multiple parallel fermentation will continue until it is stopped by the toji or ends naturally.
Temperature, sugar content, and alcohol are monitored during the fermentation. Heating or cooling jackets may be used to adjust temperature to maximize the work of the yeast and coax specific characteristics from the sake. The moromi is tested throughout the process to ensure there has been no contamination by unwanted bacteria.
After fermentation, sake must be separated from its kasu, or solids. The most common method is to use a balloon-press air compressor (assakuki); the most popular brand is Yabuta. It looks like a giant sealed accordion and, once full of fermented sake mash, inflates from the sides to gently squeeze sake through a mesh surface. The kasu is saved and used for skincare and food products. There is also a popular dish called kasujiru, a hearty, umami-rich, kasu-based soup usually containing salmon or chicken and an array of vegetables.
The air compressor is relatively delicate, but typically not gentle enough for a brewery’s most treasured (Junmai) Ginjo- or (Junmai) Daiginjo-level sake. For this, a fune, or box press, is often employed. The box contains porous cloth filter bags (shibori fukuro) and is slowly hand-filled with sake from above before pressure is applied. Though certainly more delicate, this traditional method is more labor intensive, and the risk of oxidation is higher.
The final option is the most delicate, used almost exclusively for Junmai Daiginjo sake that is often reserved for Japan’s national sake competitions. The shizuku (tear drop or gravity press) or fukuro-tsuri (hanging bag) method employs a bag (called sakabukuro) comprised of special materials and mesh not used for the normal pressing. The bag is hung inside a tank and only what drops out of the bag makes it into the bottle. One bag will usually hold 15 liters of fermented moromi, and the two-day process will yield roughly six liters of free-run sake. After the sake has dropped out of the bag, the rest may be pressed using a fune.
Once pressed, sake can go right into bottles, in which case it is known as shiboritate, or “fresh squeezed.” More often, it is moved to a tank for settling and a short, approximately 60-day maturation at a cool temperature.
Sake can be categorized into three types of pressing, though it is not always separated or labeled as such. Arabashiri (“first run”) is barely cloudy. Though it can be rough in texture, its flavors and aromas are delicate. It is occasionally sold on its own. Nakagumi (or nakadori, meaning “taken from the middle”) is usually considered the best of the three stages, with the greatest balance and structure. When separated, it is often reserved for competitions. Seme (“final run”) may be included in a batch of sake but never separated or sold on its own.
In most cases, sake is left to settle in tanks, at which point the producer determines whether to filter through activated charcoal. Non-charcoal-filtered sake is called muroka (無濾過), a term sometimes but not always appearing on the label. It retains sake’s natural greenish-yellow tinge as well as the impurities that can make a sake taste raw. It also stops the initial flavors that come along with aging and slows color change. First created in the 1960s in the Chubu Area of Niigata, the procedure was originally done in secret to hide the unique process from competitors.
The next choice is pasteurization, which deactivates heat-sensitive enzymes that may be left over from the fermentation process, preventing them from continuing to work after the sake is bottled. It also kills many microorganisms alive from the fermentation process. Most nihonshu for export is pasteurized once in tank and once in bottle. Typically, this is a quick flash pasteurization at 149°F. Twice-pasteurized sake is known as Hiire-Sake. Sake pasteurized in tank but not in bottle is called namazume. Another style called namachozo is stored in tank then transferred to bottle just before shipment and pasteurized once at that time. While temperature control is recommended for the latter two styles, they can stand slight fluctuation while still maintaining some of an unpasteurized sake’s character. These terms do not need to be stated on the label.
Unpasteurized sake is called nama (“raw” or “fresh”), hon-nama, or namazake and tastes distinctively vivacious and complex. It must be stored at constant cool temperatures of negative eight to negative five degrees Celsius, the latter considered optimal.
The timing of when the sake leaves the tank and goes into bottle is influenced by the length of maturation time intended for the bottle, storage capacity of the brewery, and pasteurization plans for the final product. Further, Japanese law dictates that sake labels must state the date of bottling but not the production date. This means producers can theoretically store sake for a year and then bottle it right before shipping.
Once sake is in the tank or bottle and ready for maturation, with pasteurization decisions made, it is left to mature for two to six months on average, often at below-zero temperatures. In 1975, Dewazakura in Yamagata became the first brewery to build a storage facility that maintained a constant low temperature. By 1991, they had developed a system for maintaining the optimal negative five degrees Celsius that could prolong the aging process of both unpasteurized and pasteurized sake. In this environment, an oxygen-reduction system is also employed.
Cedar has long been an important material in Japanese craftsmanship. The 180-milliliter masu (small wooden box) traditionally used for drinking sake was often made of Japanese cedar and imparted exotic cedar aromas. The measurement was not only used for sake service but also for purchasing rice from the local market; it is still used today when reporting production to the government. Traditionally, sake was also aged in barrel (taru); this continues for religious purposes. Some producers, such as Choryo in Nara Prefecture, are well known for their taruzake. As most barrels in Japan are produced from native cedar trees, the flavor of the taru is strong, and the sake takes on a peppery, woody aroma and a minor impression of tannin. Often, barrels are used to mask quality issues. The aging period for taruzake is not regulated and can be as short as a matter of days or even hours.
Close to bottling, breweries may add water to soften alcohol by a few degrees and bring out sweetness or mineral flavors. From here, the sake will rest in bottle or tank until the time of sale. Volumes of production are recorded for tax purposes using the measurement koku, equivalent to 180 liters.
Sake production follows a unique brewing year, or BY, that runs from July 1 to June 30. Sake releases are sold by season, and while the related terms are not legal, they are typically followed. When the first sake of the year is ready, the brewery will hang a ball made of cedar branches called a sugidama (sugi means cedar) outside of the brewery. The needles on the branches of the sugidama are green when they are hung, but by the end of the brewery season, they go brown, a symbol of the season's end. Breweries may call their first release “Sake Nouveau”; it is usually an unpasteurized, undiluted, non-charcoal filtered, freshly squeezed bottling (this could also be called Muroka Nama Genshu Shiboritate). The first sake of the year is bright, vibrant, crisp, and refreshing. Often, this sake even has a sparkle lingering from fermentation. Sold in small numbers, these bottles are sought after by sake enthusiasts. Often, new sake is submitted to the Zenkoku Shinshu Kanpyoukai, a nationwide new sake competition since 1910, where the victor wins bragging rights for the year.
Any sake released from the current brewing year is called shinshu, or “new sake.” After releasing their Sake Nouveau, breweries typically sell runs of pasteurized or unpasteurized releases until the fall. At that time, breweries pasteurize sake that has been resting in tank and release it as a fall namachozo called Hiyaoroshi. This style tends to be rounder and mellower. Natsunama is another style, stored at the brewery and released in the summer. It is often unpasteurized, but this is not mandatory.
Sake made in one brewing year and bottled in the next is called koshu, or “aged sake.” It may be released after one year or several. Because sake oxidizes and takes on a dark amber color over time, color can be an indication of koshu. Anything produced more than one brewing year ago may also be called ogoshu, or “extra aged sake.” However, these terms are not legally defined. Some producers, such as Daruma Masamune in Gifu, specialize in koshu and even release comparative sets. Kyoto’s Tsukino Katsura, a brewery established in 1675, is famous for releasing some of the nation’s oldest koshu after 50 years of aging.
Breweries release their sake when they think it is ready to drink. While sake can age, most is made to be consumed within 6 to 18 months after release—cellaring at home is usually not recommended. Producers can stamp bottles with the production date or the date of shipping, using either the Japanese or Western calendar date. Currently, there are no rules to control this, so it is important to know producer and procurer.
Water, yeast, rice, and climate all impact sake. There are subtleties even at the microclimate level that create distinctions between neighboring breweries. Due to a warmer climate and softer water, breweries in the south and west parts of Japan (Hyogo, Kyoto, and Hiroshima, for example) often produce rounder and richer sake. Further north (Niigata, Yamagata, and Akita, among others), where the climate gets much cooler for a longer period of time and the water is harder, sake tends to be more delicate, lean, and even drier.
At 80% of the finished product, water is the primary component of sake. Breweries have historically situated themselves next to a high quality water source, whether ground water, mountain runoff, or a river. Unsurprisingly, some of the most coveted locations in Japan for water are in Hyogo, Kyoto, and Hiroshima, locations where the great rice of the nation is produced. The most famous water is miyamizu, “shrine water” that runs down Mount Rokko in Hyogo Prefecture into the historical Nada area. This water is used for 25% of all sake in the country; giant breweries such as Hakutsuru, Ozeki, Shochikubai, and Kikumasamune are all located in this prefecture.
Ideal water for sake is low in iron, to avoid oxidation and adverse reactions with amino acid, and low in manganese, to avoid discoloration. Higher levels of potassium and magnesium are also preferable, as they contribute to the stabilization and flavor of sake. Harder water tends to make for a faster fermentation, and softer water fares better during longer, cooler fermentation. While Japanese water is soft compared to other major beer or whisky producing regions of the world (which also prize their water), Japan does have its pockets of hard water.
Water’s pH and mineral character will always impact the resulting sake. When no additional water is added or if the volume of water added alters the original alcohol level by less than 1%, the sake is called genshu (原酒), or “undiluted.” This is almost always noted on the label.
Yeast is essential to fermentation and impacts the final product, most notably in its aroma. Some yeasts are considered classic, others are engineered, and still others are cultivated from flowers or even mangoes. For over a century, yeast has been monitored, maintained, researched, and sold by institutes such as the Japan Brewing Society (Nihon Jouzou Kyoukai). Yeasts discovered at breweries through spontaneous fermentation may be taken to the brewing society for cultivation and sale to other kura. One of the most notable yeasts discovered at a brewery was Yeast No. 7, or Nanago, by Miyasaka Brewing Company in Nagano, circa 1946. More than half of Japan’s breweries have used this yeast, known for subtle tree fruit aromas.
The suffix “01” added to any yeast’s name indicates that it is non-foaming. This type of yeast is preferable because tanks can be filled to the top without putting quality at risk or the ferment spilling over. A yeast like the common No. 1801 will be expressive and aromatic, with exotic flower and field berry characteristics.
Yeast No. 15 was discovered in Akita in 1996 (it’s called AK-1 there). This yeast keeps acidity low and survives the particularly low ambient temperatures of Japan’s northern region of Tohoku. GE-1, drawn from the Gekkabijin flower, was discovered in Hyogo. The finished sake has a pure, white floral character. Other notable yeast varieties include YK-2911, Saitama 86, F7-01, CEL 19, Alps Yeast, and Koro. Varieties continue to be discovered and developed.
Rice quality and characteristics vary significantly. Kyoto, Hyogo, and Hiroshima Prefectures produce sake rice with definition. Most sake is produced with rice native to the region of production, though breweries in the far north will often ship rice from these locations because of their provenance. Breweries may append Ki-ippon to any of their Junmai level sake to denote that the entire production came from a single place of origin, with no ingredients outsourced.
While the Ishikawa and Yamagata GIs have globally recognized AOC status, the prefectures of Nagano, Hiroshima, Saga, Hokkaido, Niigata, and Kochi all have domestically recognized and enforced systems with varying standards. The Niigata system maintains that sake must be made with Niigata rice, while Hokkaido’s system requires 70% minimum seimaibuai and Junmai-level sake only. In Saga, there is an annual judging competition but no minimum seimaibuai. In Hiroshima, Saijo Sake status is only granted if the rice is from Hiroshima, the water is untreated, the water source is the brewery, minimum seimaibuai is 55%, and traditional sake production methods are employed. As the rules vary greatly and are only enforced at the prefectural level, these systems have struggled to gain traction. Yet momentum is shifting in favor of more control and recognition at an international level.
Created in 1936 as a cross between the Yamadaho and Watari Bune rice varieties, Yamada Nishiki is a gold standard for quality sake production. Expensive and difficult to work with, it produces complex sake with subtle fruit character. Hyogo is often cited as the best production area for the variety. Today, the prefecture is working on a new variety called Hyogo Nishiki, with hopes that it will outperform Yamada Nishiki in taste and workability.
Gohyakumangoku produces leaner, cleaner styles of sake, most famously in Niigata but also in Toyama and Fukushima. Miyama Nishiki fares well in colder temperatures and yields richer, more textural sake. It thrives in Akita and Yamagata. Omachi, the oldest rice variety used today, has been employed in sake production since 1859. It can be found in Okayama and Hiroshima. Ginginga is grown only in Iwate, Dewasansan in Yamagata, Akita Sake Komachi in Akita, and Ginpu in Hokkaido. The largest sake rice grain by size is the cold-climate-loving Hanafubuki. Kame no O is a heritage rice variety which, though not an official sake rice variety, has gained attention from producers in Niigata and northward.
Nigori (にごり酒) sake, or nigorizake, is named for its cloudy appearance. Essentially, this is sake bottled with its lees. A looser mesh is used during the pressing process, which allows more kasu to pass through during pressing. As there is no official regulation for this process, some brewers will press the sake normally and add the kasu back to the bottle afterwards. This sake is technically not “unfiltered,” because to a sake brewer, filtering is the process of passing the fermented moromi through activated charcoal. Nigorizake, then, can be called a coarse press or cloudy sake. It is usually pure white in color, with styles ranging from light bodied and dry to rich, sweet, and thick in texture. Usunigori, an only slightly cloudy sake, is a variation on the style.
Fine mesh was not used for pressing until around the close of the eighth century, so the texture-rich nigori is often seen as a traditional style. But by the end of the 19th century, nigorizake was deemed illegal due to ambiguities in production method by homebrewers and the overall innovation in sake production that had occurred by this time. Tsukino Katsura is credited with reviving nigorizake in 1964. They created a modern nigori method that controls the amount of kasu in each bottle, satisfying the Japanese regulatory office.
In sparkling sake production, moromi fermentation can be arrested while the sake is at just 8% ABV. From here, the brewery can add their own rice-based liqueur de tirage to induce the second fermentation in bottle. With no official production method and low acidity in comparison to traditional Champagne grapes, this category is a challenging one, often yielding sweet or cloying bottles. However, the greatest examples can be bright and well structured. Bunraku in Saitama Prefecture puts their sake through malolactic fermentation and performs remuage by hand to create a balanced, expressive sparkling sake. Other forms of sparkling sake include the injection method and, less often, the Charmat method. Sometimes, the kasu in the bottle will contribute to the second fermentation, leading to an appearance not unlike a non-disgorged Champagne.
Akazake (“red sake”) can be made in a variety of ways. One is using unapproved red rice varieties, letting their pigment bleed into the moromi. In Kumamoto, ash is added during production. In Niigata, a rare red koji is used. There are also yeast strains that give the finished product a red tint. Some sake is left to oxidize until it takes on an amber or reddish color. All of these are acceptable forms of red sake, though the term is unregulated.
Kijoshu is a rare style in which junmai-shu, not water, is added toward the end of the sandan shikomi process, bringing the ABV to 9 or 10%. Hiroshima’s Hanahato famously releases a sweet, mellow, eight-year-aged Kijoshu.
Zenkoji (“all koji”) results from using 100% koji and no steamed rice in the production process. It ages quickly and is naturally sweeter. Tomizu is another variant, a 150-year-old method in which the moromi has a one-to-one water-to-rice ratio by weight.
Nihonshu-do, Sake Meter Value or SMV in English, is a measurement of the specific gravity of sake: the density of sake compared to the density of water. It is measured with a hydrometer sunk into a graduated cylinder full of sake. The measurement itself is 10 times more precise than the Baumé scale used in beer and wine production. Most often, this number ranges from -4 to +14, where higher is drier.
This measurement is important during the brewing process, but it’s rarely used or discussed after that. Nihonshu-do is not a legal term, nor does it appear on most small-scale breweries’ labels. It is a very specific measurement that doesn’t consider factors like acid or chemicals that contribute to the flavor of a sake and the perception of dryness or sweetness. Because of this as well as its inconsistency, it is not part of modern sake assessment or promotion. However, it is important to know as it still sometimes appears on sake menus in Japan and in sake importers’ catalogues.
San-do, or acidity, is occasionally denoted on a bottle. The number refers to the milliliters of liquid sodium hydroxide that would be required to neutralize 10 milliliters of sake and typically ranges from about 0.8 (sweeter) to 2.0 (drier).
Amino acid is also key to the makeup of sake, contributing to the flavor and longevity of sake. The level of amino acid may be noted as the number of milliliters of liquid sodium hydroxide plus formalin required to neutralize 10 milliliters of sake. This value is usually between 0.8 and 1.2. A lower number demonstrates delicacy (wateriness if very extreme), and a higher number corresponds with richness (sake with a very high amino acid number can be cloying). Sake with a high amino acid count will age faster.
These numbers do not account for quality or balance and ultimately are not very helpful in understanding the characteristics of sake. More helpful for when discussing preferred styles are terms like karakuchi (dry) or amakuchi (sweet), and kaori (aromatic) or aji (textural, savory).
Sake prices tend to be fair based on the materials and methods used. There is often a direct correlation of price to pasteurization and the related costs. Seimaibuai is also a factor: when more rice is polished away, a higher volume of rice is required. The reputation of the kuramoto (brewery owner), quality of rice used, size of the harvest, and the use of machinery versus hand craftsmanship are also factors. While these factors can certainly affect the taste of a final product, expensive does not necessarily mean better.
The following information must be stated on sake labels, as enforced by Japanese law: ingredients, liquid volume, product type (nihonshu and seishu are both acceptable terms), bottling date, brewery name and address, alcohol content, and a warning that sake cannot be sold to or consumed by minors. Other commonly listed information includes style (such as Junmai), type (such as nama), seimaibuai, origin, and type of rice.
Labels are a continuous concern, as even many Japanese people cannot read the traditional Kanji (simplified Chinese) on labels. Thankfully, the key terms are usually legible and are no harder than memorizing wine label terms. Also, many producers are releasing English labels, a trend that is not correlated with inferior quality. Though Japanese can be hard to read, pronunciation is not as daunting as it seems. It is a phonetic language without tones or inflection; it is relatively easy to pronounce after picking up the nation’s unique set of alphabets.
Most exported sake is pasteurized at least once, so while some temperature fluctuation may not be a problem, it is best to keep sake out of the sun and at a constant temperature, if not in a wine fridge. Many breweries and sake shops wrap bottles in newspaper to avoid UV exposure. Since it has no cork, sake can be stored right-side up.
When sake goes bad, usually due to heat or oxidation, it becomes overly sweet and heady, with a white, foaming sediment. This condition is called hi-ochi or hine, referring to a stale, uncharacteristic, caramel-like odor. Even without cork enclosures, TCA is possible—though very rare—due to bacteria contamination from wooden components used in sake production.
Though hot sake is perhaps best known in Western culture, most sake is consumed slightly chilled. Traditionally, sake was rounder and heavier than it is today, due to production methods and storage in wooden barrels rather than stainless steel. That style of sake was often served at a warmer temperature, which showcased the weightier character. Today’s more delicate sake is typically better at a lower temperature, preserving elegance. This raises the sensation of dryness and brings balance to the sake, though it may also mute some of the subtleties, both good and bad.
Sake can, however, benefit from different serving temperatures. At room temperature, sake can show more depth and richness. This is a great test for nuance and evaluating whether the sake has been stored and cared for properly, as the warmer temperature can expose flaws in production or storage. Served warm, umami and sweetness come forward on the palate. But warmed too much, many volatile compounds and aromas are lost. Serving sake warm is acceptable in many cases; serving it hot is rarely acceptable.
It is best to serve unpasteurized, fruit-forward, delicate, and/or aromatic sake cold and to serve savory, earthy, and/or aged sake at room temperature or warmer. To warm sake, it is poured into a copper vessel called a Chirori and placed in a warming apparatus called an okanban (a term also used for the person responsible for warming the sake).
There is one tiny, sake-focused izakaya in Hong Kong called Godenya (located in Ginza until 2015) that serves each sake of its tasting menu at a different temperature, carefully determined by its proprietor, Goshima San.
Sake is typically portioned out in multiples of 90. Bottles are 720 (yongo) or 1,800 (issho-bin) milliliters. Sometimes, a 360-milliliter tokkuri (carafe) is served. One portion is usually measured into a 180-milliliter sake serving vessel and called ichi-go.
The drinking vessel can impact sake’s flavor and should be selected based on the situation. Traditional earthenware sakazuki and the small white porcelain ochoko are common. Japanese ceramics have a rich history that dates back even further than sake production. For formal assessment, though not for competition, the Japan National Research Institute of Brewing uses a standard 180-milliliter tasting vessel called kiki-choko that is made from white ceramic and has two blue circles at the bottom of the cup. The circles highlight the subtle green and yellow tinge that naturally occurs in sake. The lip of the vessel, much thicker than that of a wine glass, affects the taste of the sake. Most sake makers also use this cup when deciding whether a sake is ready for bottling, though some use an ISO wine glass.
In a beverage program, a sake selection of even a few bottles can offer genuine contrast, giving guests the opportunity to taste the diversity of sake and develop their own preferences. Sake can fit anywhere, from aperitif to dessert. While a diverse sake-pairing menu can easily be executed with any number of international food styles, sake can also be served alongside beer and wine. In Japan, it is very common to start with a draft beer before moving to sake, or to enjoy an easy-drinking beer alongside sake through the meal.
If serving sake in a restaurant, present the bottle to the guest who ordered it and state the name of the sake. Open the sake and offer a taste to the guest; upon approval, pour a glass for each guest at the table, working clockwise. Fill the glass of the guest who ordered last, regardless of gender.
In Japanese culture, sake signifies reverence, family, and friendship. Traditionally, drinkers should never pour their own sake; instead, people should pour for one another. With that in mind, consider offering to leave the bottle on the table, rather than keeping it at the side station. When a bottle is kept on a table, watch to see if the guests are pouring for each other and step in if needed.
Sake is an extremely versatile beverage, one that can play a compelling role beyond the Japanese restaurants to which it has often been relegated in the past. Despite its millennia of history, sake is an evolving category—a benefit of occasionally murky standards and a result of brewers’ ongoing passion for this historic beverage.
Compiled by Elliot Faber (June 2017).
Love the guide above, incredible detail!
For anyone interested, here is a great brochure I found put together by the National Tax Agency of Japan - Japan GI Information 2025
Thanks, and enjoy
Thanks, Ben! This is updated.
"After fermentation, rice must be separated from its kasu, or solids. The most common method is to use a balloon-press air compressor (assakuki); the most popular brand is Yabuta. It looks like a giant sealed accordion and, once full of fermented sake mash, inflates from the sides to gently squeeze sake through a mesh surface. The kasu is saved and used for skincare and food products. There is also a popular dish called kasujiru, a hearty, umami-rich, kasu-based soup usually containing salmon or chicken and an array of vegetables." - Should this read "sake must be separated from its kasu?
Ah, thank you for the clarification. My error was partly because I didn't realize that most commercial freezers are much colder than that range. Interesting, Niizawa stores all of its bottled sake, not just Namazake, at -5˚C in order to better preserve freshness.
Hey William! We recommend -5˚ as it is just above the temperature where sake will freeze. This is to mitigate any biological activity within an unpasteurized sake. This is a technique made popular by the Nizawa kura.
I believe the stated storage temps for Namazake are incorrect. Most references I see say that it should be stored below 5 degrees Celsius, and as far as I'm aware you should not be storing your sake below freezing.
Hey Victoria! This is confirmed and updated. Thank you!
Ichigo is 180mL (not 90mL) and Nigo 360mL. It's based on the size of a masu, which is approx.180mL.
Hey Michael! Thanks for catching the typo. It is fixed! Kasu is roughly "unfermented rice solids" which aligns more with pomace than lees.
Is "pomacebo" a typo for "pomace" in the definition of kasu? Other sources also describe kasu as "lees."