‘Soya is an emulsifier that helps chocolate flow through machines more easily and stops the cocoa solids and cocoa butter splitting,’ explains Willie. ‘But it has a very particular aftertaste, which most people think is part of the chocolate. It’s not until you taste chocolate made without it that you realise how much it can hide the flavour of the beans. Most industrial producers also add lots of vanilla, as that covers up the fact that the beans they’re using are low quality and don’t actually taste particularly interesting, or even nice.’

As you can probably guess, there isn’t an emulsifier or vanilla bean in sight at Willie’s factory, nestled away in the Devonian countryside. It’s all about the cacao, and the naturally complex flavours good cacao beans contain. The whole process from start to finish is truly artisan, with machines similar to the melangeur mentioned earlier chugging away, grinding, roasting, shelling and conching (a process which removes the acidity and unwanted flavours from the cacao). ‘At the turn of the twentieth century there must have been hundreds of chocolatiers doing what we do,’ explains Willie. ‘But in the 1950s when production really ramped up, they started introducing soya so the machines could run all day without blocking. We’ve been trying to tell people about soya for years as it’s the biggest epiphany you can have when it comes to chocolate.’

The average bar of Willie’s Cacao has just three ingredients – cacao, natural cocoa butter and raw cane sugar (plus milk if it's a bar of milk chocolate) – and the flavours Willie manages to get out of his beans are, quite simply, astonishing. You’d swear the Peruvian Chulucanas contains raisins, or that the Columbian Los Llanos has been infused with dark cherries and plums. But to truly appreciate just how much time and effort it takes to make each bar (industrial chocolate can be made in a matter of hours and your average artisan takes a few days; Willie conches his beans for around three weeks at low temperatures to prevent the precious flavours from being damaged), you have to go back to where it all started – on a remote cacao plantation in Choroní, Venezuela.

Willie certainly had an unorthodox upbringing, spending his childhood on the tiny Horse Island in County Cork. ‘We had goats for milk, bees for honey, fields for the barley, wheat and oats, a huge vegetable garden, we hunted and fished and salted things for the winter,’ he says. ‘It left me with a great understanding of where food comes from.’

Living this self-sufficient, open-to-the-elements life instilled a passion for exploration in Willie, and he spent much of his early adult life travelling the world. But he hadn’t even thought about chocolate until he was trekking around South America in the early 1990s with his wife at the time Tania. ‘Back then there wasn’t any tourism – it was like being an explorer,’ he says. ‘There weren’t any stands to buy tickets to see ancient Peruvian mud cities; you just walked around them! When we were in Venezuela, a Columbian artist we’d met told us about Choroní, this incredible place 'where the mountains meet the sea'. We spent some time there living on the beach when Mervin, the guy who rented the umbrellas, told us about his friend who was looking to sell his cacao farm.’

While he had absolutely no interest in buying the farm, Willie was never one to say no to an interesting experience, so he went to check it out. What he found was a breathtaking hacienda, its grounds stretching right up the side of a mountain, peeking through the clouds at its highest point. He was in love. ‘There were nutmeg trees on the lawn, mango trees of every different type growing, cashew nuts, annatto – every conceivable thing. When we arrived the cacao plantation was in full crop and there were these multi-coloured pods everywhere. I’d never seen anything like it, and we jumped at the chance to stay there for a while.’

During his time there, two of the farmhands (who still work for Willie to this day) got out a little iron pan, some cacao beans, a little coffee grinder, a lump of raw cane sugar and a bamboo spoon and mixed up some chocolate for Willie to drink. ‘To this day I remember how incredible I felt afterwards,’ he says. ‘I realised I – and in fact most people – didn’t really know anything about chocolate. I’d definitely caught the cacao bug.’

Willie had finally found what he wanted to do with his life, so he started to look at how he could buy the farm. The whole process took over two years, but Willie’s sheer determination (plus a little bit of luck) meant he finally had the keys to Hacienda El Tesoro. In a sense, that was the easy part – the next few years saw Willie turn the farm into one of the best cacao plantations in Venezuela. ‘I had many happy years there, planted 10,000 cacao trees, made mango and nutmeg marmalades, had a little restaurant, rented out hammocks and rooms, everything,’ he says. ‘We even ran an international school there for seventy children.’

Throughout Willie’s years at the farm he spent as much time as he could learning about and making chocolate. He already had a reputation locally – after all, he was a somewhat eccentric Englishman living in a remote Venezuelan community – but word started to spread about the quality of chocolate he was producing. ‘I had this neat little trick of using UHT cream to make truffles, and people started inviting me to their haciendas so I could show them how to do it. I loved discovering all these different flavour profiles from the beans.’

In 2007, Willie decided it was time to return to the UK and create a chocolate factory, so he could share what he’d discovered on his farm in Venezuela. Lacking the huge amount of money needed to buy new, modern chocolate-making equipment, he spent years sourcing all the antique grinders, old ball roasters and longitudinal conching tanks he could get his hands on. This, as luck happened, suited Willie perfectly.

‘Growing up on a small Irish island meant that whenever something broke down we had to fix it ourselves, which left me with a natural knack for tinkering with machines and mechanics,’ he explains. ‘Modern machines are all software-based, which make them a lot harder to fix when they go wrong, but I find mechanical problems much easier to solve. When I came back to the UK and finally got my hands on some chocolate-making machines, they were mostly broken or had parts missing, so I had to rebuild them. I always knew I could make the chocolate – what I didn’t realise was how much better it would be using proper machines instead of just a bamboo spoon and a hand grinder back on the farm.’

What started as a needs-must assortment of machines quickly turned into a full-blown collection. Today, Willie has chocolate-making machines of every type in every size, and he talks about his melangeurs, roasters and conchers with as much enthusiasm as he does for the cacao that goes into them.

‘I bought this roaster from a bakery in France for next to nothing five years ago,’ he tells me, darting around one of his many sheds full of weird and wonderful machines. ‘These conchers are from the 1880s and I got them from a little factory in Menorca, not a place you’d think would make chocolate. There’s a French vibration table over there, and something called a pinmill that turns cocoa solids into powder. This triple grinder I got from the north of Spain – I had to get permission from the mayor of the town to close the street so the truck could pick it up!’

A lot has happened since Willie’s chocolate factory opened a decade ago. He starred in his own TV series in 2008, something he believes was what got his products into twenty-five Waitrose stores when he was first starting out. He sources the finest beans from all over the world, using his experience as a cacao farmer to work directly with the growers; this means he can ask them to change the post-harvest process so the beans have the exact flavour profile he's looking for (just one day more or less of fermentation can make a world of difference). Trading directly this way is actually better for the farmers than Fair Trade because the money goes directly to them and Willie never pays less than $500 a tonne over world cocoa prices (compared to the standard $150 for Fair Trade). This is clearly something that frustrates him – his method of working is better than any certified standard, but it can be hard to get this message across to people.

Willie has also branched out into producing flavoured bars, matching specific flavour profiles of different beans with everything from lime and ginger to hazelnut and raisin. It’s impossible not to compare him with Willy Wonka – he even has the name to match. But Willie hasn’t even begun to do what he’s always wanted: open the world’s best working chocolate factory and museum.

If you haven’t realised it yet, Willie’s Cacao is like nothing else out there. There isn’t any soya or vanilla altering the flavour of the beans; the artisan processes used tease out all kinds of incredible fruity, nutty, smoky flavours from the world’s best cacao and there’s a whole host of different bars, truffles and powders to try. It really is incredible trying it for the first time, especially when you realise that all the chocolate you’ve eaten before does, in fact, taste mostly of vanilla flavouring and emulsifiers. But just making and selling the chocolate isn’t enough for Willie – he wants to educate people about this wonder-ingredient, and he hopes his dreams for a working chocolate factory and museum (which, he says, will be based somewhere inside the M25) will make this a reality.

‘It’s going to be a place where everyone can walk around and see chocolate being made from scratch with all the beautiful machines I’ve collected over the years,’ he says. ‘At the top will be a greenhouse with cacao trees growing, then the sub-level will be where you can taste, see and smell all the different beans, a bit like a wine cellar. We could have live feeds showing what’s going on at the farm in Venezuela, do tastings of different beans and cane sugars, look into the antioxidants and flavonoids chocolate contains – all sorts.

‘The working factory and museum is why I get out of bed in the morning,’ he continues. ‘We’re not that far away from making it a reality – I’ve got all the machines, so it’s not a pipe dream. It just solidifies who we are. So many people visit Cadbury World each year but you don’t actually see anything real – it’s like a theme park.’

What I thought would be a brief day out in Devon eating delicious chocolate and learning a bit about how it’s made turned out to be a full-blown cacao epiphany. Even without all the stories of romping through the Venezuelan jungle and seeing all sorts of wild and wonderful machines churning out unctuous liquid chocolate, the simple realisation that most chocolate – even supposedly high-quality chocolate – really just tastes of sugar, vanilla and soya was dumbfounding. Willie reckons there are around ten people in the UK producing true bean-to-bar chocolate, but none are able to source beans and make it quite like he does. I’m not sure I’ve met anyone who has as much passion (some might say obsession) for one single ingredient, and I think it’s that which makes Willie’s Cacao so good. ‘For me, chocolate is an incredibly powerful narcotic and I am totally hooked on it,’ Willie says as the day draws to a close. ‘I just think about it all the time. The plan isn’t to make lots of money or sell the company and retire. All the future holds is more chocolate.’