What are fukurozuri and tobinkakoi? The pinnacle of craft brewing, pursued despite terrible yields

Putting everything into one "Shizuku" (drop)

Sake has a "pressing method."

This process of extracting only the liquid from the moromi (fermented mash) might commonly be imagined as mechanical pressing, but in the world of the highest quality sake, an ancient method that relies solely on gravity still survives.

That is fukurozuri (bag hanging), and the container used to carefully store the sake born from it is a tobin (large bottle). The combination is called "tobin kakoi (bottle storage)."

Our brewery holds a liquor manufacturing license for other brewed alcoholic beverages, not a sake license.

As producers of doburoku (unrefined sake) and craft brewed beverages using fruit, we actually incorporate this "fukurozuri and tobin kakoi" technique.

This time, I want to honestly explore the essence of this pressing method, including its background.

Reference: National Tax Agency "Standards for Manufacturing and Quality Labeling of Sake" (National Tax Agency Public Notice No. 8 of 1989, revised by National Tax Agency Public Notice No. 30 of 2022)

What is Fukurozuri? Zero-pressure pressing

The fermented moromi is placed in a cloth bag called a sakabukuro (sake bag) (mainly made of cotton), and then hung over a tank or rod and left there.

Without applying any external pressure, only the drops that seep out due to the moromi's own weight are collected in a receiving vessel.

That's all there is to fukurozuri.

It sounds simple, but in reality, it's a very delicate process.

The material and sewing precision of the bag, temperature control during hanging, the hygiene of the receiving vessel, and above all, time.

A process that would take a few hours with a press can sometimes take several days with fukurozuri.

Since enzymes and yeast are alive in the sake bag, if the temperature rises, the precious aroma can dissipate, or off-flavors can develop.

Maintaining a low-temperature environment, we patiently wait for it to drip.

The resulting liquid has high clarity, with almost no lees (sediment) mixed in from pressing.

The aroma is delicate, and because no components that cause off-flavors are introduced, it has a very clean taste.

This method is often used for ginjo-style sake because it aims to preserve the gorgeous aroma created through low-temperature fermentation without damaging it with unnecessary stress.

What is Tobinkakoi? The prestige contained in an 18-liter vessel.

The container that receives the drops obtained from fukurozuri is a "tobin." Since it holds one "to" (a traditional unit of volume), it's like a present-day 18-liter can, a bottle with the capacity of 10 one-sho bottles.

The unit "to" is an ancient Japanese unit of volume, with 1 to equal to 10 sho, which is approximately 18 liters (the equivalent of 10 1.8L one-sho bottles) (Note: 1 to is precisely 18.039L, but it's often treated as 18L in practice).

A tobin refers to a glass flask-shaped container of that volume.

The term "tobin kakoi" refers to the entire process, including receiving the naturally dripping sake from fukurozuri into this tobin and then "kakou" (enclosing), meaning storing and aging it at low temperatures.

Tobin are wrapped in cloth or covers to block light and stored in a refrigerated environment at around 0℃.

During this low-temperature aging period, the still young sake quietly settles, its aroma improves, and its flavor gains depth.

Freshly pressed fukurozuri sake can retain a "young bitterness."

If this is bottled in a hurry, it can give a rough impression. That's why it's important to store it in a tobin and age it over time.

Fukurozuri and tobin kakoi can be said to be techniques that function as a set.

 

Yield is "the worst" - is this praise or an insult?

In manufacturing, "yield" refers to the proportion of final product obtained from raw materials.

The yield of fukurozuri is significantly lower compared to regular press-pressing.

In regular mechanical pressing, when separating sake from sake lees from the moromi, a lot of liquid can be squeezed out by applying pressure.

On the other hand, fukurozuri only relies on gravity, so a considerable amount of liquid remains in the sake bag when finished. If that sake bag were squeezed hard, more liquid would come out, but then it would no longer be "fukurozuri."

Intuitively speaking, if the same amount of moromi is subjected to regular pressing and fukurozuri, the amount of sake obtained from fukurozuri is several tens of percent less.

While pressing yields 80 to 90%, fukurozuri yields about 50%.

The amount absorbed by the sake bag and the amount that didn't drip due to gravity are all losses.

From a business perspective, this is "financially insane."

The same raw material costs and brewing effort result in a significantly smaller product yield. Moreover, the working time is also longer.

From the perspective of product cost, fukurozuri is a method that is structurally destined to be expensive.

Nevertheless, brewers and sake makers adhere to fukurozuri because there is value beyond cost.

 

Why isn't it widely available on the market? The stage of the sake competition.

Sake made with fukurozuri and tobin kakoi is rarely seen on regular liquor shelves. There's a good reason for that.

One of the most prestigious judging events in the world of sake is the "National New Sake Competition."

This competition, held annually since 1911 (Meiji 44), is co-sponsored by the National Research Institute of Brewing and the Japan Sake and Shochu Makers Association, where breweries nationwide submit their new sake.

It's a place where each brewery brings a bottle that embodies the essence of their techniques, in pursuit of the honor of a gold medal or prize.

Many of the sakes submitted to this competition are brewed using fukurozuri and tobin kakoi.

This is because sake obtained through this method is the pinnacle of "that brewery's best technique and ingredients," and its clean quality makes it easy for judges to evaluate.

Conversely, it has a strong characteristic of being sake made specifically for the competition.

It's no exaggeration to say that the competition sake from a particular brewery and the regularly distributed sake of the same brand are two different things.

There may only be a few dozen bottles of competition sake, and it's often limited to those involved or sold in limited quantities.

As pointed out in the article on the "National New Sake Competition," there's a structural reason why "the submitted sake is only the best part made by that production facility and rarely goes into general circulation."

 

From Wikipedia

Sake made with fukurozuri and tobin kakoi is difficult to find on the market because the quantity is small, the cost is high, and it's allocated for special purposes like competitions.

 

The context of "other brewed beverages" license, fukurozuri, and doburoku

According to Article 3, Item 19 of the Liquor Tax Act (Act No. 6 of 1953), cloudy sake made by fermenting rice, rice koji, and water and finished without straining is classified as "other brewed alcoholic beverages."

What is generally called doburoku falls into this category.

On the other hand, products that have undergone the straining process (= joso) become sake, and the license category also differs.

Our brewery holds a "liquor manufacturing license for other brewed alcoholic beverages," not a sake license.

In other words, what we produce is, legally speaking, not sake, but craft brewed beverages such as doburoku.

So, what does it mean to apply fukurozuri to doburoku and craft brewed beverages?

It refers to the approach of gently separating the liquid portion from the moromi of fruit-fermented beverages using the fukurozuri technique.

What is obtained by fukurozuri fruit moromi is a liquid with transparency and delicate fruit aromas, which is distinctly different from pressure extraction.

The pigments, tannins, and astringent components in fruits are extracted more when pressure is applied.

Fukurozuri can minimize this elution, akin to skimming off only the core of the fruit's original aroma and taste.

 

Fruit Fukurozuri: Our Brewery's Challenge

At our brewery, we perform fukurozuri for craft brewed beverages using seasonal fruits.

This is an attempt to combine the culture of doburoku with the ideas of craft beer and wine, and finish fruit fermented liquids with fukurozuri.

This is an attempt to apply techniques refined in the sake competition culture to new ingredients and new sake qualities.

Honestly, we know the yield is poor. We also know the cost will be high.

Nevertheless, we choose this method because we want to deliver the delicate aroma and texture of the fruit as unspoiled as possible.

If we press forcefully, the quantity will increase.

But I feel that "something" inherent in it would be lost.

Normally, such sake is not easily available on the market.

Due to the small quantity, we often announce it through visits to our store or limited invitations. Please regularly check our social media and in-store information.

 

The true nature of what resides in a single drop

The techniques of fukurozuri and tobin kakoi are, in terms of efficiency, cost, and yield, not "rational" at all; one might even say they are the worst.

Yet, this method has survived for hundreds of years, and there's a reason for that.

By not using the "force" of pressure, only what the moromi inherently possesses quietly drips out. There are no off-flavors, no excessive astringency, no unnecessary stress.

Fukurozuri is a technique of subtraction.

Rather than adding to enhance value, it preserves the purity of the ingredients by not adding anything superfluous. Tobinkakoi can be seen as the act of entrusting that delicate sake to time and a gentle low-temperature environment, allowing it to mature quietly.

This philosophy also applies to the world of craft brewed beverages and doburoku.

If the ingredients are good, then we should interfere as little as possible.

One answer to this is our fruit fukurozuri.

The next time you pick up a bottle, please try to imagine how many drops gathered to make that quantity.