"The problem is that tea is no longer made for flavour. It's made to satisfy the teabag market," says Bernard Holsinger, a consultant and senior resident tea planter at Ceylon Tea Trails in Sri Lanka's Central Highlands. "You Brits just can't wait five minutes for it to brew."

What Holsinger, a great teddy bear of a man, doesn't know about tea isn't worth knowing – he began his career as a trainee tea planter more than 50 years ago, and went on to manage several estates. Today he works for Dilmah – one of Sri Lanka's biggest tea producers – as well as running his own artisanal estate and homestay, Ebony Springs.

According to Holsinger, the best way to make the perfect cup of black tea goes something like this: swirl boiling water around a teapot to warm it before adding freshly boiled, good-quality – filtered if you live in London – water and 2.5g of tea leaves (or a tea bag) per cup, stirring as you go. Leave it to brew for three minutes. Pour the tea into warm teacups, and decant any tea remaining in the pot to avoid over-brewing. Then you can think about flavour enhancers, whether that's milk, a slice of lemon, or in Sri Lankan style, a piece of jaggery (palm sugar).

I witness this technique to its fullest effect when I'm brought bed tea on my first morning. Yep, that's tea, delivered to me in bed (or to the door of my room, if you want to get technical about it), the leaves brewing in a large porcelain pot and served with cold, full-fat milk on the side. It's delicious: bright and flavoursome, comforting me from the inside out. The tea I buy and drink excessive quantities of at home in London quite literally pales in comparison.

For a drink that seemingly consists of just some dried leaves and hot water, tea has held a huge amount of sway over Britain. We've been chugging cups of the stuff since 1657, when tea was first sold publicly in London.

By 1800, it had become the most popular drink in the country – practically fuelling the British Empire when it was at its peak.

THE TEA PLUCKERS

THE TEA PLUCKERS

When the British brought tea to Ceylon, they resettled thousands of Tamil people from southern India to look after the estates. Tea plucking remains the domain of Tamil women, who pick up to 16kg of tea leaves a day. Today, most estates run crèches or offer their workers other forms of support. One example is Dilmah's MJF Charitable Foundation. One of its initiatives is to provide aid for the pluckers, giving them three months' maternity leave, and access to an on-site dispensary with 24-hour service and free transport to the local hospital if required. Nursery, schooling and nutrition is provided for children, where they're taught Tamil and the Sri Lankan Singhal language, as well as English.

There was only one problem: all the tea in the world was grown and produced in China, and we greedy, tea-glugging Brits couldn't control the price. Originally, the East India Company would trade opium in return for China's tea leaves – until the Emperor put his foot down when he realised this was creating a nation of drug addicts. England needed to find another way to pay for its tea, or produce it in a way it could control.

The East India Company sent in a young Scottish botanist, Robert Fortune, to steal some tea trees and learn the closely guarded secrets of how the Chinese made their tea. He was successful, taking seeds from China to India – then under the control of the British Empire. Within his lifetime, India surpassed China as the world's largest tea grower, and the story became known as the Great British Tea Heist. Very sneaky.

Tea went on to make its way from India to Ceylon, or modern Sri Lanka, when the teardrop-shaped island was afflicted with coffee rust, killing all the crops. Another Brit, James Taylor, saw this as an opportunity and set up Ceylon's first tea plantation in Kandy in the Central Highlands, and by 1872 the first shipment of 10kg of Ceylon tea arrived in London. It turns out Sri Lanka's sunshine and cool nights make for perfect growing conditions, producing a tender leaf.

Now, in 2018, tea bushes cover a whopping 25% of Sri Lanka's surface. But for all that, tea drinking in Britain has declined. And it's no surprise given that we've been consuming a watered-down version of a drink we originally loved so much.

There are, according to Bernard, three reasons for this. First, the brewing method, then the leaves themselves – tea sold in the UK tends to be one or two years old by the time it reaches the shelf, when it's already lost most of its flavour – and then, despite many packets claiming to be Ceylon tea, they'll only contain about 10% of the stuff; the rest is padded out with lesser-quality tea harvested elsewhere. Bearing this in mind, I make a mental note to check the packet next time I hit the shops in search of a caffeine fix.

But what exactly is it that makes ceylon tea so incredibly highly prized? I learn that it comes down to the method of harvesting and processing. "In Sri Lanka, tea is picked by hand, and the quality of the raw material is of a high standard," says Holsinger. "In other countries where tea is also hand picked, the leaves aren't of the same quality."

While there are still large tea factories in Sri Lanka, it's become better-known for artisanal brands. One of its most successful is Dilmah, the country's first grower's brand that was set up 30 years ago by one Merrill J Fernando, who spotted a gap in the market for 100% Ceylon tea. Until then, most of the tea companies were owned by foreigners. Fernando pioneered a model for adding value to an old-world crop, while keeping the system ethical, and going to rare lengths to provide care for his tea pluckers.

tea in the uk tends to be one or two years old by the time it hits the shelf

All of the Dilmah profits remain in the country, and the company has been so successful that Fernando's son Malik opened Ceylon Tea Trails – a collection of unused tea plantation bungalows around Lake Castlereagh in the Bogawantalawa Valley in Sri Lanka's tea country that previously served as homes for the planters that oversaw the estates. It was in one of these bungalows that Holsinger lived, working as general manager on the Norwood Estate.

Fernando Jr converted the buildings into luxury guesthouses, where you can now stay, trekking, cycling or being driven between them. Unsurprisingly, 40-60% of the guests come from tea-drinking countries, and one of the main activities is a visit to the tea factory at Dunkeld Estate, also home to one of Ceylon Tea Trails' bungalows.

It's here that I learn about how tea is grown in varying agro-climatic zones and elevations, from sea level to 7,000ft above it. Each micro-climatic zone produces tea with its own taste, flavour and character – low countries produce fashionable leafy grades (large-leaf), while high areas produce tiny leaves. The larger the leaf particle, the lighter the tea, while tea bags need unexciting-sounding 'dust', which infuses much quicker and gives you more cups of tea per kilogram, but results in a substandard cup.

Decoding the vocabulary around speciality tea

Tea Words

Decoding the vocabulary around speciality tea

Bakey

Unpleasant taste usually caused by very high temperatures and driving out too much moisture during the firing process

Body

A tea possessing fullness and strength

Brisk

A lively taste in the tea, as opposed to a taste that's flat or soft

Cream

The precipitate the develops on cooled tea. A bright cream denotes that you've got a good-quality tea

Dull

A tea lacking in flavour, caused by bacterial contamination, faulty firing or excessive moisture

Flat

Lacking in briskness. This is caused by age or faulty storage

I also learn that creating good tea starts with the camellia sinensis bush. Here, very few chemical repellents are needed – the mature leaves lower down the tree are so full of tannins they deter diseases and critters that are keen to munch the leaves. The leaves are picked by an army of pluckers using a special technique – pinching off shoots with two tender leaves and a bud – once every eight to ten days. Some trees at Dunkeld estate are 140 years old; the younger ones a mere 60.

The leaves are then brought to the factory, where they're withered over hot air for 12 hours, reducing their moisture content from 75% to 45%. The leaves are then 'rolled' under a metal roller, which begins to crush them, releasing their juices and kicking off the oxidation process. When the tea leaves are left to ferment, they turn from green to brown in colour and change from what we know as green tea to black.

Once dried, the leaves go into a hopper – a sorting machine, not the delicious Sri Lankan breakfast staple – which determines the different leaf sizes. For example, a grade-eight leaf involves the leaves being passed through a square inch with eight holes in it. The leaves are then dried in large baking ovens. This method is called CTC – which stands for cut, tear, curl – and is considered the most sophisticated because it involves very little human contact that would otherwise spoil the tea.

The next day, I rise early to go for a run: too much tea (12 cups at the last count, not to mention tea-laced cocktails) the previous day made for an erratic night's sleep. I plod around the steep roads that run through the rows of tea bushes. With all the trees at exactly the same height, it makes the area look like a giant manicured garden, with ethereal mist rising off the plants as the day begins to warm up. My path is interrupted as a river of bouncing school children, the tea pluckers' kids, streams past me, running through the bushes in white shirts and blue trousers or skirts, their plaits bouncing as shouts and giggles fly through the air.

I'm forced to pause and drink in the view, not to mention the smell – the humidity and fragrance of the air makes it feel as if I'm going for a bath in a giant teapot. And as I turn back, making sure I've got time for one last cup, I think that this – artisanal produce, made in a way that's sustainable for land and people – is really what it all boils down to.

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