Inside a 160-year-old Japanese Rice Cracker Factory

[machine chugging and whirring]

[Narrator] How does this non-glutinous rice starch noodle

turn into this crunchy snack,

which happens to be the most popular snack in Japan?

These crackers called senbei were introduced

to Japan over a thousand years ago,

and they are typically served with green tea.

And this factory called Ikedaya

has been making senbei in a traditional style

outside of Tokyo for over 160 years.

[Akira speaking in a foreign language]

[Narrator] Inside the factory that Akira Ikeda runs,

we can see the entire senbei process from start to finish.

The process starts with a 100%

non-glutinous short-grain rice,

which is milled into a fine flour.

About 90% of the factory's production is done

based on orders from clients.

So, the amount of flour milled varies from day to day.

The factory's biggest clients are the famous sumo stadiums

across Japan who order an exceptionally dense rice cracker

with an intense snap.

The rice is ground into flour with a metal blade,

which is sharpened once every two years.

On a normal day,

the factory mills one ton of rice into flour.

The flour needs to be exceptionally fine

in order to make a consistent and uniform cracker.

One person is in charge of a milling process

from beginning to end.

This takes about three hours, starting at 6:00 AM.

After being grounded and sifted in manageable batches,

the flour is stored in paper bags

with the aid of a bamboo basket and a wooden hoe.

[machine chugging and whirring]

Every 15 minutes throughout the milling process,

freshly milled rice flour is moved

to aluminum measuring containers

and then it into a machine called

[speaking in foreign language]

The flour is then steamed in a process

similar to cooking rice in a rice cooker.

The dough that results from this stage of processing

can be hard or soft, depending on amount of water added,

which is changed to make different types of senbei.

[container clanking] [machine chugging]

For this recipe, he's using six buckets of rice

and three buckets of water.

The precise amount of water is calibrated

depending on the humidity in the air.

In order to achieve the perfect consistency of dough

inside the machine, the dough is kneaded

and then clamped shut.

[machine whistling and chugging]

Pressure builds

and the dough is steam-cooked for 10 minutes.

After 10 minutes, the dough is extruded into warm water

that's kept at 40 degrees Celsius,

so that the thick rice noodle or dough called 'shinko'

is able to cool slowly.

This step removes bitterness

and makes sure a hard skin doesn't form.

[machine chugging and whirring]

A new factory worker monitors the temperature of the dough,

which takes about one hour to cool.

He's also monitoring the hardness

and softness of the shinko throughout this stage.

[machine continues chugging and whirring]

[water burbling]

When the worker deems it's ready,

the dough is removed from the cooling bath.

Then he loads the dough into a kneading

and extruding machine referred to as

[speaking in foreign language]

[machine whirring]

At this stage, the extruded dough is smoother

and more refined than it was when it was extruded

into the warm water bath.

Each step of the process is crucial

for developing the dough's properties

with a desire to viscosity and consistency.

A smoother dough will lead to the ideal texture

and expand the characteristics in a final product.

This elastic blob may look like softer,

but it actually has a consistency of Silly Putty.

Next, the dough is pounded in a mill stone

in a process called [speaking in foreign language]

The dough is constantly moved to the center of the stone

for consistent and uniform agitation.

Through this process, air is knocked out of the dough,

and starch is extracted from the cell of the rice,

forming into a polysaccharide

or long chains of glucose molecules linked together.

This creates a strong elastic and chewy dough.

Throughout this stage, the factory worker

has a bucket of water on hand

to make sure the dough doesn't dry out too much during

[speaking in foreign language]

Though this specific batch of senbei has no other flavors,

the senbei crackers comes in a variety of flavors,

including shrimp, sesame seeds, and mustard.

When making flavored senbei,

these other ingredients will be added to the dough.

The now firm dough is formed and folded into a bowl

and cut into two portions, which will each be used

to make one batch of the senbei crackers.

In this cross section,

you can see how uniform the dough is,

sticky, smooth, and paste-like without any visible grains.

This machine is a stamp press.

At this stage, dough is loaded into the back of the machine

and then pressed into long sheets.

The pressed dough is stamped on a metal screen

in a wooden frame.

Inside the machine, a cylindrical die,

perforated metal plate, that roll over the dough to cut

and shape it into consistent circular discs.

The screens with six rows of circular discs are inspected

for any imperfections or misshaped dough.

[machine chugging and whirring]

Any that don't meet the craftspeople's standards

are thrown back to be recut by the die.

Excess or scraps are reused from each sheet,

so no dough is wasted.

Here you can see the loading end of the machine

before a new sheet is rolled out and cut by the die.

[machine whirring]

The cut discs are dried in a floor to ceiling dehydrator.

Small and thin senbei dry for three hours,

while thicker rounds of dough

destined for harder-baked senbei

dry for four and a half hours.

In the winter,

these thicker rounds take up to five hours to dry.

While the senbei doughs we have seen thus far

are all round disks,

there are a number of shapes

that the factory can create using differently shaped dies,

from small circles to flowers,

praying hands, fish, and small faces.

Here, you can see the die being changed out

for differently shaped senbei.

These are shaped as open palm prayer hands, decorative fans,

and little faces.

[machine whirring and clanking]

According to the rules of Soka city,

only expert artisan craft people called 'shokunin'

can work in traditional industries.

It usually takes more than 10 years of training

and apprenticeship to acquire technical mastery

and pass a test to become a shokunin.

Being a shokunin signifies

more than just being a skilled craftsman or artisan.

It encompasses a deep philosophical approach

to work and life.

[metal clanking]

The metal screens that hold the senbei allow

for air circulation and even drying.

Historically, this step used to involve sun drying

for several days.

After being cut and dehydrated,

the senbei are stored for 10 days in wooden boxes.

The resulting discs are dehydrated, dense,

and very hard like a rice puck.

Next, the senbei are conditioned in a machine called

[speaking in foreign language]

for two hours during which they're warmed

and tumbled to give them a polish.

Then the senbei move through an

[speaking in foreign language]

a pressed baking machine

in a process that takes a total of three minutes.

[machine whirring] [metal clanking]

Here, we can see the craft person in charge of this area

loading the machine.

The packs are stacked,

and then suctioned up with pneumatic tubes

and moved to a conveyor belt.

[machine whirring]

The senbei are then flipped across the heating element

that toast them for about five seconds per side at a time.

[machine whirring] [metal clanking]

Halfway through the baking process,

air bubbles start to form on thicker senbei,

so these baking crackers are pressed

to maintain shape and texture.

If this didn't happen, the final crackers might fall apart

and will have a large bubbles that shatter when bitten into.

[machine whirring] [metal clanking]

After baking, the senbei travel down a chute and up a ramp.

[machine whirring]

Then the senbei roll, standing up on their edge

through a soy sauce trough.

The soy sauce is pumped up

from the reservoir up to the trough.

As they roll, soy sauce is being applied

to the cracker's perimeter.

[machine whirring]

Then brushes apply more soy sauce to both faces

of each cracker.

Now, as you can see,

the senbei have their classic golden brown color.

And once these have cooled,

they're ready to be packaged and sold.

And that is how senbei is made.

[Akira speaking in a foreign language]

[Akira continues speaking in a foreign language]