Tea plants in a greenhouse of Local Tea in Zundert Netherlands with WUR Vision+Robotics' test setup for a mobile tea factory

Revolution in tea: building a smart tea machine

10 July 2024

A mobile machine that automates the entire artisanal tea production process. You put in fresh tea leaves and out come green, oolong or black tea. Visiting LocalTea in Zundert, the Netherlands.

There it is. The world’s first machine that automates and optimises the artisanal tea process. Equipped with sensors that meticulously measure and monitor that process. To make tea from the Netherlands. Specifically, from Zundert. Vincent van Gogh was born in this village in the Kempen region of Brabant, for many years a very poor area. Sandy ground, poor soil. But apparently ideal for plant nurseries. Vincent’s village is therefore known as an epicentre for growers.

One of the growers 16 years ago was Johan Jansen from Special Plants Zundert. He specialised in unusual plant species. When travelling around China, he was captivated by the rich flavour of artisanal tea or rather the tea plant, Camellia Sinensis. Why can’t I market these in the Netherlands, he wondered. Not tea, but the plant. He went looking for species that could thrive in the Dutch climate. And there were plenty of those. You find tea plantations on the slopes of the Himalayas, where it is quite a bit colder than in the Netherlands. Sri Lanka even has plantations above 2000 metres – yes, it’s a tropical region but it can still be chilly at night. But not many tea plants can survive in the cold wet climate of the Netherlands. But Jansen wasn’t giving up. He continued to search, select and cross-select. He recorded the species that perform best in our country. With the help of crowdfunding and investors, he started his own tea plantation in Zundert. And his own tea: LocalTea. With a slightly childish packaging featuring windmills and Dutch flags. Nevertheless, an interesting addition to the tea shelf: tea from the Netherlands.

Tea strangely does not inspire innovation

In 2022, Wouter Eckelmans became Director at LocalTea. Born in Leuven, in Belgian Flanders, he lives near Gouda. His background is the tea world of Unilever and Douwe Egberts. During a visit to a tea plantation in Sri Lanka, he saw the terrible conditions in which people live and work there. Like serfs, completely dependent on the plantation owner. A sad remnant of the colonial past. Alcoholism and the misery associated with it is widespread on the plantations. It is a similar situation in other plantations around the world, according to reports by journalists. Eckelmans was irritated by tea companies continuing to highlight the schools or hospitals they are building and everything else they do for their employees, all while failing to address the root cause of the problem. When he came across LocalTea, he saw a great opportunity to do better. In terms of fairness, sustainability and quality.

At LocalTea, they were looking for a Managing Director. Someone who could further professionalise the company and the breeding process. Exactly what Eckelmans wanted. He loves tea. “It’s such a lovely product, which strangely does not seem to inspire much in the way of innovation.” Shareholders of big tea companies are not very interested in that. Their main concern is lining their own pockets. Breakthrough innovations tend to cost money. The only innovations you see in the tea industry are new flavours. The tea bag is more than 100 years old. Yes, Lipton introduced a pyramid shape. But even that was 20 years ago.

LocalTea director Wouter Eckelmans poses with a tea plant

Managing Director Wouter Eckelmans

Belgian beer as an example

They’ve been making tea the same way in Asia for centuries. Eckelmans: “The beauty of a craft and traditions is that people stick to them. But it can also limit you in terms of innovation and creativity.” A good example is how the Belgians and Germans approach beer. Our eastern neighbours work according to the Reinheitsgebot, a series of regulations which limit the ingredients used in brewing beer to malted barley, hops, water and yeast. All other ingredients like spices and fruit are banned from the brewing process. A regulation going back to 1516. The Belgians don’t have a purity regulation. So they say, let’s be creative. Which is why they have such a wide range of beers. “Dutch winemaker Ilja Gort doesn’t care about restrictive French wine rules either. He says, I’m going to make the best possible wine in this place and with the knowledge I have.”

Greenhouses and foil tunnels

Eckelmans shows us around the plantation. 7 hectares, with 1.7 million tea plants. A bit further on, 7 hectares are ready for greenhouses and foil tunnels. Tea plants grow just fine outdoors, he says. “They don’t mind a frost.” One drawback: in the open, he can only harvest twice a year at most. In the greenhouse, he can harvest six times. Without heating. In the Zundert sunshine, the temperature inside quickly rises to 20 or 30 degrees.

Making tea is labour-intensive. It starts with the picking. The best leaves, the ‘two leaves and a bud’, grow on top of the plant from March to September. Besides craftsmanship, the secret to the best quality tea lies in those leaves and bud, says Eckelmans. At LocalTea, they pick by machine, with human precision. “We then let the leaves wilt: you wither them for about two to eight hours which makes them lose a certain percentage of their moisture.” To make green tea, the leaves undergo the ‘kill-green process’. “Heating the leaves stops the oxidation process. Like spinach, they shrink. How long do you heat them? That depends on the flavour you want to bring out.” The leaves then go in the roller that opens the cell walls of the leaf. “This releases the essential oils and all the flavourings. Once the tea starts to stick, you’re done.” The final part: drying the leaves in a big dryer. “They are ready to use when they are dark and hard, and break when you squeeze them.”

500 flavours

Tea maker Frank Verboven from LocalTea has been making tea in Zundert for years. Based on sight and touch. He looks at a leaf and sees whether it is good or not. However, he can never be entirely sure. ‘It might be a hot day and then the leaf will lose its moisture more quickly,” says Eckelmans. “If you make the whole process fully controllable, in an air-conditioned room, you have a constant in what you do. And that’s what we are aiming for. To improve the quality.” With a measurement at each step of the process, always for one type of tea. For other tea types, you have different standards to consider. “We will soon be able to feed that machine with information. I want to make this type of green tea, so you automatically get the standards that apply to a sencha tea, Japanese green tea, a pan-fired tea or a type of hojicha tea. That’s what I love about tea. You can extract as many as 500 flavours from that plant and blend it with the most deliciously pure ingredients.” Also important: “You can make that automated process mobile. One stop. You put the tea leaf in and it comes out ready to use. So that you can use that machine on multiple plantations.” But LocalTea must be truly local. Eckelmans doesn’t want to serve the whole of Europe from Zundert. But from tea plantations in different places in different countries. “Local, so more sustainable and less transportation.”

Local Tea tea-maker Frank Verboven working the rolling machine, the second step in the tea-making process

LocalTea artisanal tea-maker Frank Verboven working a tea rolling machine.

Automate, manage, and control the artisanal tea process

He is enrolling LocalTea in the NXTGEN Hightech programme. An umbrella initiative that aims to encourage SMEs to invest in technological advances. For a NXTGEN Hightech project, you have to look for at least three partners. He teams up with WUR Vision+Robotics researchers and machine builder Van Wees Waalwijk. To develop a one-stop tea machine together. First step: see if and how you can automate, manage and control the artisanal tea process. WUR researchers are analysing what happens when in the tea leaf during that production process, and whether you can monitor and control it, says research associate Fátima Pereira de Silva. To that end, they replicated the entire tea-making process in separate parts. To dry the tea, they used their own drying oven. To roll the tea, they acquired a roller. “We performed the oxidation in an air-conditioned room at a constant temperature and humidity.”

Tea measuring test setup with sensors by WUR Vision+Robotics researchers at Local Tea in Zundert

Test measurement setup with sensors

For each part of the production process, from withering to drying, WUR researchers checked which image, near-infrared and volatile sensors are best suited for what. Pereira de Silva: “With a volatile sensor, you measure aromas and the intensity with which they are released.” With near-infrared, you can establish how much water and other substances a tea leaf consists of. Near Infrared Spectroscopy (NIR) can be used to measure dry matter and polyphenols. “The latter indicates how much oxidation has taken place in your tea leaves. Polyphenols react with oxygen. That causes a brown colour change.”

Sensors monitor and measure final tea quality

Oxidation, and rolling and heating the tea leaves are key flavour components. Colour is also a relevant parameter, says Pereira de Silva. Which can be monitored by image sensors. “You can then adjust the process more to the left or right because the leaf is becoming too light or too dark.” Now that the machine is in place in Zundert (‘from a laboratory situation we are moving to a production environment’), you can also use the sensors to monitor the overall process and measure the final quality. This results in a hefty dataset that the machine can eventually use to learn on the job. Pereira de Silva: “You’re talking about quite a complex matrix. With an initial quality that changes, a product that always reacts differently to the production process and a final quality that varies.” Fully automating the entire artisan process is an ambitious plan, but not impossible. Compare it to building a bridge while crossing it. “We don’t yet have much understanding of how all the process parameters affect tea production and quality. We hope to figure that out using sensors. But first we need to train them. So that there’s a link between what the sensor measures and the tea properties you want to measure.”

A smart tea machine

Eckelmans hopes to complete the NXTGEN Hightech project in 2026. By that time, the mobile tea machine should have arrived. He smiles at the idea. A machine that knows, right, I’m making black tea now, which means I oxidise the tea leaves after withering and after the roller to get a deep sweet flavour. This is going to revolutionise the world of tea. Although: “Continuing to exploit people will unfortunately still be more lucrative for many plantation owners than buying such an expensive tea machine. It’s going to make our tea even more sustainable, fairer and tastier.”

Paul Goethals Vision Robotics

ir. PHI (Paul) Goethals MSc

Business Development Manager

Contact ir. PHI (Paul) Goethals MSc