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This is what happens inside a Japanese tea factory

Join me as I guide you through a Japanese sencha factory and show you how tea is made.

Mel Hattie
Mel Hattie
11 min read
This is what happens inside a Japanese tea factory

Most of us only see one phase of tea, the dried leaves that end up in our cup. If you’re drinking tea from a tea bag, you might actually never see your tea at all. Between the bush and cup tea takes an exciting journey with many steps that takes them from being a fresh leaf to a finished product. Let’s take a look at what that looks like in a Japanese tea factory with the country's most popular tea—sencha.

The sencha factory I get to work in here in Wazuka belongs to Obubu Tea Farms where I’m living. Obubu hosts weekly tea tours that take guests through the fields, factory, and then for tea flight tastings back at Obubu house.

The factory is literally right across the street from Obubu house, where our dormitories are. My bedroom here actually looks on to it.

View of the tea factory from my window.

This is where I look out every night before I go to bed to see if they’re still processing tea. During the busy season, they can be up until 2 or 4 a.m.

The Obubu building used for processing sencha was originally an udon factory but was abandoned in March of 2000. In October 2016, the Obubu team of interns, plus co-founder Hiro and his Dad cleaned the factory up and tuned it up for sencha processing. They’ve been making Japanese sencha tea here since 2017.

Seeing all the guest slippers lined up at the factory is strangely satisfying. Gotta love that organized Japanese life. Guest slippers have to be lined up just right.

Let's get this show on the road.

Okay, are you guys ready for your tour?

Making sencha in Japan

Sencha is Japan’s most popular tea. About 80% of what the country makes is this steamed green tea, easily steeped and love by all. Found in vending machines and kitchens across the country.

The tea is known for its fresh flavour and bright green liquor. It was originally created around 300 years ago in Kyoto region. Around 100 years ago, tea processing machines were invented. 60 years ago, tea harvesting machines were invented. As demand grew, sencha processing technology grew with it.

To give you an idea of the life cycle of a farming day, the farming team will be out in the fields around 7:30 a.m. They’ll have a lunch break, then continue in the afternoon. After a supper break, they’ll meet back in the factory around 7 p.m. or so, and start processing the leaf.

On a good day, a team of about three people can harvest around 70 bags that weigh around 40 pounds each. A team of 2-3 people can finished processing between 11 p.m. and midnight, but sometimes when the season gets crazy, that can extend to 2 a.m. or later. The whole machine-process takes about 4 hours from start till finish, and needs at least two people.

Bags full of fresh tea are left in the factory and wait to be processed

99.9% of tea in Japan is machine-harvested and machine-processed. If you’re wondering why it’s not done by hand, let me throw some numbers at you.

In the same time it takes to process 3 kg of hand-rolled tea with a team of six people, you can process 50 kg or more with machines, and need only two people.

The math makes it obvious that machine processing is more economically viable than hand-rolling, especially when you consider the global tea market has competition in places like India, where tea pickers might make only a dollar a day—less than that in some places.

The good news is, all tea from Japan is fair trade, because the labour laws and implementation here are much better. They also make a sweet-tasting green tea like no other.

Perfect for naps during those long processing nights.

Tea holding container

Welcome to the first step of making green tea! Because green tea is essentially non-oxidized, it has to be processed as quickly as possible, otherwise it'll turn into brown and we'll lose all that delicious, fresh flavour.

Japanese name—Namaha contena (生葉コンテナ)

Usually the tea is just laid out in its bags on the floor as it’s brought in by the farming team. They’ll fluff the leaves in the bag out into a doughnut shape with a hole in the middle. This helps keeps the leaves cool as they lay on the floor and wait for processing.

Sometimes, during big harvesting days we collect more than we can process in one night at the factory. When this happens, we add the leaves to these large containers.

The containers have fans at the bottom and cool air is blown through every 15 minutes to keep the leaves cool and limit oxidation. When piled in here, they can keep good for about 12 hours. However, we rarely use them because we usually process everything the day it comes in.

Conveyor belt

Japanese name—Kyuuyouki 給葉機

When we’re ready to starting processing, we start dumping the bags of tea leaves into this conveyer belt. This feeds the leaves into the steaming machine.

Steaming machine

Japanese name—Mushiki 蒸機

This is the steaming machine! This first process is unique to Japan, as many other green teas (such as most Chinese green teas) are pan roasted. The steaming that happens here is to kill the enzymes in the leaf, and also gives Japanese tea its unique flavour.

The red boiler on the right hand side heats water and sends it to the steaming machine. The water needs to be at least 70˚ C in order to kill the enzymes, stop oxidation, and keep the leaves’ bright green colour and fresh flavour.

The leaves need to be steamed for about 20-60 seconds. How long exactly depends on the toughness of the leaf. Brand new spring sencha baby shoots will only need 20-30 seconds, whereas big ol’ bancha leaves from later in the season will need a longer time.

When the leaves are ready they drop down into a chamber at the end of the steamer where they’re sucked up by a vacuum tube and carried to the next step.

Leaves travel by vacuum through this tube, jettisoning in two seconds or less into the cooling chamber.

Cooling chamber

Japanese name—Reikyakuki 冷却機, the cooling chamber, is the wire cage which sits on top of the soft rolling machine (below).

The cooling chambers sits here on top of the soft rolling machine. As the leaf is sucked through the tube it cools down before landing in the cage.

This cage will hold around 60 kg of tea leaf. When it gets full, the red light on the left will light up and let us know that it’s time to pull a lever to release the leaves into the soft rolling machine below.

Soft Rolling Machine

Japanese name—Daiichisojuki 第一粗揉機

From here on out, all the machines’ actions have one goal: to shape the tea and reduce moisture content. At this point, with the steaming the tea will have a moisture content of around 400%. We want to get it down to 5% by the end.

Old school Japanese hand-rolling was how tea used to be processed before the advent of machine driven factories, and all the rolling machines we’re going to look at next help shape the tea the same way human hands would have.

The paddles in this machine press the leaves against the walls of the machine, shaped like in a cylinder and lined with bamboo. This helps release flavour. The forks then grab the leaves and toss them in the air to dry them. The paddles and forks continue to spin, and hot air is being blown to dry the leaves at around 90˚ C at the same time.

Even though the tea is being processed by machines, tea creation here is still a hands-on process, with the lead farmers checking the leaves periodically to see if they’re progressing as they should, because factors like humidity and rain can change how long the leaves need to stay in each stage along the way.

Sencha tea will stay in the soft rolling machine for about 30 minutes.

For the rest of the tour, I’m going to take you through the artisanal production line on the left, for small batches of 25 kg or less. Mostly because I think the machines are a bit more charming, but they’re essentially just smaller versions of the large batch ones.

Rough rolling machine

Japanese name—Dainisojuki 第二粗揉機
Japanese name—Dainisojuki 第二粗揉機

So, this machine is basically the same as the soft rolling machine, except with more pressure to get more moisture out of the leaf. There’s also hot air being blown in at this stage, but it’s a bit cooler than the 90˚ C from the soft rolling machine. The leaves’ moisture content should be around 70% when finished here.

The tea leaves will stay in the rough rolling machine for about 30 minutes.

Rolling and twisting machine

Japanese name—Jyunenki 揉捻機

This is my favourite machine in the whole sencha factory! Isn’t it so adorable and charming?

At 67 years old, this twisting and rolling machine is an antique. It’s gorgeous old wood and exposed mechanisms are the best. This one was donated to us by a retired tea farmer.

The tea is placed in what looks like the bottomless ‘pot’ on top, and then the weight is brought down on top of it. The weight rolls and twists to make sure all the leaves get even contact with the surface below as the pot swings around in a circle.

So far as we’ve been drying in the first two rolling machines we’ve gotten the moisture out of the edges of the leaf, but there’s still moisture hiding in the stems and center of the leaf. This process helps brings the moisture out evenly, and the rolling also breaks the cell walls and releases more flavour.

Middle rolling machine

Japanese name—Chujuki 中揉機
The middle rolling machine is lined with bamboo on the inside.

So at this stage we’ve been rolling the leaves so much, they’ve become clumped up. It kind of reminds me of when you’re mowing a lawn and the grass sticks together in tufts.

This machine separates the clumped together leaves and also continues the drying process. If you were doing this by hand, at this stage you’d have to pick every individual leaf out of the grassy tea ball.

Inside the chamber this machine is also lined with bamboo (I’m sensing a theme, here), and the arms move the leaves around while the tea is heated again. After this stage, the tea will have around 30% moisture left.

As they tumble through this machine, they’ll become separated into individual leaves and be ready to go onto the final rolling stage.

Final rolling machine

Japanese name—Seijuki 精揉機

We’ve finally arrived at the pièce de résistance of machine Japanese tea. This machine creates the needle shape of Japanese sencha. Japanese tea has been made in a needle shape for around 280 years.

The final rolling machine creates the needle shape by pushing the leaf back and forth through paddles and brushes until it comes out needle-thin and ready to bust through some Japanese washi paper.

This machine imitates the hand rolling motion to make the needle shape. This shape is unique to Japan, and has been made for 280 years. It was originally created to make it easier to transport, since the compact needle shape was much more volume efficient.

If you’re interested in what hand-rolling looks like, you can read about my experience waking up early in the morning to pick and hand-roll sencha.

The levers with red handles on this machine are weights that can be adjusted based on the feel and shape of the leaf. Our lead farmer and co-founder here at Obubu, Akky-san, will monitor this step closely to make sure the leaf's final shape is turning out right.

After the leaves are finished in this machine, they’ll have around 10% moisture. This final rolling process takes 45 minutes to an hour. This process also heats the tea from below.

After this, we only have one step left to get the moisture down to 5%.

Drying machine

Japanese name—Kansouki 乾燥機

Surprise! The final step is drying the leaves so there’s only 5% moisture left in them.

When the leaves are ready, they’re poured in the trough on the left. There’s a conveyor belt here that lifts them up and lays them down on a belt that goes back and forth through the machine. At the end of each row there’s a little trap door where the leaves fall down. This is so they flip over and dry evenly on each side.

Inside the tea drying machine.

As the tea travels along the drying machine, small particles of the tea that have broken off, but are still good quality, fall through the holes in the belt and down below.

They fall down chutes where they’re collected in small tins.

Fine particles that break off from the larger leaf are collected at the bottom. This is a tea bag grade tea.

This is what goes in your tea bags!

Most tea bags you find in the stores are this ‘dust’ grade tea. I mean, in its own way they’re good—dust means a higher surface area to water ratio, so you can get a quicker infusion. Just looking on the bright side.

The final product, ‘aracha,’ which is raw tea, or farmer’s tea, falls out into these pans. This is where we collected out beautiful, finished leaf! This will go on to be packaged as loose leaf tea.

The tea is now ready to drink!

Large bags of packed tea. These are the kinds of tea bags you often see at the tea auction in Kyoto. Kind of like ‘bales’ of tea.

Normally in Japan this tea would then be packed into bulk bags and taken to auction where larger wholesale companies would buy it, sort it (separate stems from leaf), blend it (to their company’s flavour profile), and sell it, either under their own label, or to another company to do with it what they will.

At Obubu, they sell the raw tea directly to consumers, kind of like a vineyard, where you can taste the different profiles of the fields each season, Obubu sells raw tea so its customers can have a direct connection to the farmers and fields of Wazuka. This means their flavour profile also changes with the seasons and years.

No two are exactly alike.


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