Narrator: To make sake, you need a lot of rice.
Brewers polish rice into pristine, pearl-like grains
and combine it with koji mold to craft the perfect flavor.
You can buy a bottle of sake for less than $10.
But the most expensive version of the highest grade,
called junmai daiginjo,
can cost almost $10,000.
Sake requires just four ingredients.
But without careful attention,
the brew can be ruined at any stage.
At Niizawa Brewery,
Nanami Watanabe observes the entire process.
She's one of the youngest brewmasters in Japan.
Narrator: Despite her age,
her sake has already won several awards.
Narrator: We spent a day with Nanami
to discover how she brews sake
and to learn about what makes junmai daiginjo so expensive.
It's a quiet morning in the mountain town of Kawasaki
in Japan's Miyagi Prefecture.
But inside the brewery, the hustle has already begun.
Narrator: Sake is categorized by its ingredients
and the degree of rice polishing,
also referred to as the rice-polishing ratio.
To be considered junmai daiginjo,
at least 50% of the grain
must be removed through polishing.
The more polished the rice,
the longer the sake takes to make
and the more expensive the final product.
The brewery uses around 12 metric tons
of unpolished rice per week.
To polish rice, brewers run it through mills
that remove the sides of the grain,
which contain proteins and fats.
Narrator: Compared to the umami flavor
of sake made from less polished rice,
more polishing generally means a cleaner taste
and a more expensive price point.
But before it can be fermented,
it has to be washed and steamed.
Narrator: Workers move quickly
because every moment counts when washing rice.
Narrator: Now it's time to steam the rice
that workers washed yesterday.
Narrator: Steaming takes around 40 to 45 minutes,
and just like washing, it requires close attention.
Narrator: For Iwao, promoting Nanami to brewmaster
at a young age wasn't much of a risk.
Narrator: Nanami has been working at this brewery
for seven years.
Narrator: It takes roughly 2 kilos of rice
to make a 1.8-liter bottle of sake.
Many different types of rice can be used,
which affect the taste and the price.
Niizawa Brewery sources most of its rice locally.
Narrator: While ordinary junmai daiginjo sake
uses rice polished to at least 50%,
Niizawa's most expensive sake
is polished to less than 1%.
Narrator: Polishing rice to 50% takes around three days.
But to get to 1%,
it takes over 200 days.
The process requires more rice
and slower, more careful polishing.
Niizawa makes around 1,000 bottles
of this type of sake each year,
and Iwao says they always sell out.
Narrator: But polishing is just the beginning.
Once the rice is steamed,
it's time to add the most important ingredient,
koji mold spores.
Koji is a type of mold that grows on steamed rice.
As the spores grow,
they convert the starches in the rice into sugars.
But workers have to move quickly
to maintain the correct temperature and humidity.
They feel for warm and cold areas of the rice
and move clumps around to keep the temperature even.
Narrator: Once the koji is ready,
Nanami combines everything in large fermentation tanks.
Narrator: Koji turns starches into sugars,
and the yeast converts those sugars into alcohol.
This process is called multiple parallel fermentation;
it's what makes sake unique.
It's also what makes brewing it so challenging.
Nanami monitors this liquid, called mash,
every day for a month.
There's a lot of anticipation waiting to taste the sake.
She takes samples and uses sensors
to track the fermentation.
Narrator: After it ferments,
the mash is pressed and bottled as sake.
But no matter the price of the bottle,
Nanami ensures every sip is delicious.
Narrator: For Nanami, training her palate
is just as important as honing her brewing skills.
After work, she often tastes sake from other breweries.
Narrator: Nanami ordered nine kinds of sake,
but she doesn't know which is which.
Narrator: Despite sake's legacy in Japan,
Nanami says it isn't always the drink of choice
for people her age.
Narrator: Tasting sake in a restaurant while eating
allows Nanami to experience it
the same way a customer would.
Narrator: Now it's time to check how many she got right.
Narrator: Niizawa Brewery has been around
for 150 years.
Iwao Niizawa is the fifth generation to run it.
Narrator: At the age of 25, Iwao became a brewmaster.
He dedicated himself to improving the quality
of the sake and the brewery's sales.
But in 2011, disaster struck:
A magnitude 9 earthquake and the resulting tsunami
devastated the northeastern coast of Japan.
Narrator: Since rebuilding,
Niizawa has won numerous awards for its sake.
And Iwao has passed the role of brewmaster to Nanami.