THE slate grey shipping container tucked up a side street in Glasgow’s east end does not look like a chocolate factory. It does smell like one, though. From the bitter scent of the cocoa nibs stacked up ready for grinding; to the delicious aroma of liquid chocolate in the tempering machine, once you step inside, there is no mistaking it.

Chocolate is everywhere. It is in the big plastic trays, stacked up ready for decanting and hand-wrapping; it is in the giant, industrial fridge, which takes up a huge chunk of the container, cooling to just the right temperature; and it is in the boxes, neatly wrapped in foil and bold, bright labels, poised and ready to be distributed to shops and cafes around the city and beyond.

But this is no ordinary chocolate. This is Rebel Chocolate, brainchild of Neil Robson and Suzanne Graham, who met on a PhD course in immunology and who have applied their vast scientific knowledge to the question all chocoholics really, really want answered.

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How can we make chocolate healthy and still have it taste so good?

The answer, according to Rebel, is to cut out half of the sugar, add 25 per cent protein and make it lactose-free – although Robson is very quick to point out that his chocolate is merely healthier than the stuff we are all used to.

“Please note the ‘ier’ at the end,” grins Robson. “We are not saying this is a health product. It’s great-tasting chocolate, but with a nutritional twist…”

Born in Southampton with an English mother and a father from Glasgow, Robson grew up in New Zealand.

He came to Scotland to study immunology, firstly at Edinburgh University and then at the University of Glasgow, where his work concentrated on developing a potential vaccine for glandular fever.

A serious back injury, sustained during a martial arts training session, left him in considerable pain and when surgery to correct it failed, he was left, he says, “wondering what the hell I was going to do with my life.”

He explains: “Staying in academia would probably have meant lecturing, and there was no way I could stand for long periods of time, or work 60-hour weeks.

“I was lying in bed one night, thinking about what to do next, and the idea of creating a new kind of snack bar came into my head.

“I started wondering – could you add protein to chocolate? Could you actually re-formulate chocolate to make it healthier? Cocoa has great health benefits, but I believe the high levels of sugar found in most chocolate outweighs those benefits.”

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The idea took hold and Rebel Chocolate was born. Firstly, in the couple’s kitchen in the west end of Glasgow, with the help of a small nut grinder bought from a specialist store, and latterly, in the shipping container as part of Glasgow Collective, an interesting coworking set-up in the Barrowlands area of the east end.

“I wasn’t interested in doing things that had been done before, that’s just boring,” says Robson, slowly. “I’m a scientist. I wanted to do something new and inventive. But always, I want to create something that tastes great. It can be an innovative product, but it has to be a treat.”

It took several months of tasting and testing before the duo was happy with the end result – and the first bars went on sale one year ago. “It was a good moment,” agrees Robson, with a smile.

Suppliers already range from Kimble’s, Tinderbox and Peckhams in Glasgow to coffee shops, delis and garden centres across Scotland and in England and Wales. A bodybuilding shop, Better Bodies, has also become a supporter and some “interesting” big name brands have approached Robson about stocking Rebel.

“I’m delighted to be on their radar already, but we will have to expand to increase capacity,” he admits, adding firmly: “But we plan to stay in Glasgow. We love being here, at the Glasgow Collective, which is home to some pretty cool, creative businesses.”

He adds: “I’d love to set up Rebel Chocolate Australasia – my family are in New Zealand, Suzanne’s are here, so it would make sense to have a base in both places.”

More space and machinery are on the wish-list, and by next Easter, Robson is hoping to have a range of chocolate eggs on the market too.

“We’re likely to be a bit busier this Easter – perhaps from people looking for a healthier alternative to what’s available, even though we are not selling eggs yet,” he says.

“We’re not a chocolatier, so we are not into fancy decorations and mouldings, or creating fillings – although we are thinking about introducing some flavours. We did a crystallised ginger chocolate recently, which got great feedback.”

Robson, 45, taught himself how to make chocolate, painstakingly researching and creating the three main bars Rebel launched last year – Belgian, Madagascan and Colombian. The company now produces a white chocolate too.

“I really did start with a bar of cheap chocolate, added some whey protein and waited to see what would happen,” he recalls.

“It was eight months of experimentation. At the start I was working part-time at the university, and Suzanne still works as a senior manager in the NHS, so it has been hard work. But it has become a passion for both of us.”

Graham, 39, handles the social media, website and marketing side of the business, while Robson works in the chocolate factory, making and wrapping the chocolate bars.

Although the couple use modern nutritional knowledge and more than a little science in the formulation of the chocolate, it is made the “old fashioned” way, using stone on stone grinders.

Ingredients blend together for around four to five days, in a process called refining and conching, before being tempered, the method which creates “shiny, snappy” chocolate.

“You have to make sure the temperature is correct – even the moulds have to be warmed up before you put the liquid chocolate inside them, or you’ll get the wrong kind of finish,” explains Robson.

Recently, he has been joined by an assistant chocolate-maker, Alain Baron, through the Scottish Government’s Access to Work scheme.

“Alain helps me with the physical side of the job,” says Robson. “Sometimes my back can cause me a lot of pain, so this has been fantastic for me and the business.”

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Despite the career switch from immunology to chocolate-making, Robson’s science background is never far away from his thinking.

“I’ve also been doing some research into adding CBD to chocolate – it’s a non-narcotic used to reduce pain,” he says.

“I live with chronic pain – it’s why setting up the business has been perfect for me, because it’s flexible. I can sit down when I need to, I can rest when I need to.”

He laughs: “So making a chocolate bar that could actually help reduce pain sounds like a great idea to me.”

In case it sounds like all the fun is being taken out of chocolate, Robson is quick to reassure.

“Chocolate IS fun and it tastes amazing and it’s a real treat for most people,” he says, with a grin. “Ours is all of that, but it comes with less guilt.”

FIVE MORE CHOCOLATE-MAKERS AROUND SCOTLAND

Chocolate Tree, Edinburgh

Award-winning craft chocolate from a company which prides itself on protecting dioversity and rewarding farmers by paying a premium for their crops. Owner Alastair Gower travels to Peru, Colombia, Venezuela and Madagascar to buy cacao, and the team in Edinburgh roast, winnow, grind and conch the cacao in small batches. Its chocolaterie on Bruntsfield Place is open for visitors.

Lime Tree Larder

Sitting at the end of a lime tree avenue (planted by Grandpa Wilson in 1927) on Auchencloigh Farm, in Kilbirnie, Ayrshire, this family run business specialises in handmade chocolates and artisan ice cream. As well as running chocolate workshops and parties the company organises group and school visits to learn about the origin of chocolate.

Cocoa Ooze

Creative chocolatier Jamie Hutcheon set up Cocoa Ooze in Aberdeen 10 years ago, when he was just 17 and training to be a pastry chef. The small team now makes beautiful chocolates for all occasions, supplying a range of outlets around the world.

James of Arran

The Arran Chocolate Factory has been producing handmade chocolates for almost two decades, and their mouthwatering handmade truffles and fudges, champagne and ginger, mandarin marzipan and passion-fruit crème-filled chocolates are legendary on the island and around Scotland.

Highland Chocolatier

Iain Burnett, based in Grandtully in Perthshire, handmakes all sorts of spiced pralines and dipped fruits, but it is his Velvet Truffles which have brought him worldwide recognition as a Master Chocolatier. Using a single-origin cocoa from the South Atlantic island of São Tomé – known for its rich volcanic soils - plus crushed fruits, exotic spices and unblended fresh Scottish cream from a single herd of cows in Perthshire, the signature truffle has won more than 40 prestigious awards.