A teenager who boosted his pocket money by selling homemade jam has had to move production out of his parents’ kitchen after winning a supermarket deal.

Fraser Doherty was 14 when he started bubbling up vats of jam from his grandmother’s recipe book and selling them to friends and neighbours after school. Within four years he was producing up to 1,000 jars a week from his parents’ home in an Edinburgh suburb.

Now he is being credited with reinvigorating an old-fashioned market with his imaginative range of products, including kiwi fruit, lime and ginger preserve and lemon marmalade.

His contract to produce 120,000 jars for Waitrose, thought to be worth six figures, means that his parents will no longer be asked to label jars and taste new recipes, with production moving to a small factory in Herefordshire. The range, to be called SuperJam, is expected to sell for £1.49 a jar in 130 stores.

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Mr Doherty, now 18 and studying business and accountancy at Strathclyde University in Glasgow, said yesterday: “If things continue to go so well I plan to take on extra staff, and I would love to have the product in other supermarket chains, too. I’m hoping that SuperJam will help encourage a new generation of jam fans.”

The teenager started playing around with jams after his grandmother taught him a recipe for marmalade that had been handed down through generations of the family. With her help he began to invent his own unusual jams, selling them door to door in Edinburgh, but also supplying farmers’ markets, delicatessens and even Hibernian Football Club.

In 2004, when he was 15, he so impressed a panel of business experts that he was given an Enterprising Young Brit award by Gordon Brown, the Chancellor of the Exchequer.

Traditional jams are made of up to 80 per cent sugar, but Mr Doherty, whose company is called Doherty’s Preserves, has developed a healthy alternative, using grape juice instead of artificial sweeteners or sugar. He said: “I wanted to make jam in as healthy a way as possible. Traditional jam is quite unhealthy. It is boiled in huge pans so it has no nutritional value, whereas my jam is much more healthy.

“It was quite daunting to change a product that has been made the same way for hundreds of years, but I wanted to put a completely new perspective on jam.”

Michael Simpson-Jones, the preserve buyer for Waitrose, said: “Fraser has managed to take a product with a slightly stuffy and old-fashioned image and completely reinvent it, giving it a young and more up-to-date image.”

Mr Doherty’s father, Robert, said that he would miss the sight and the commotion of the jams being made in the family home in Davidson’s Mains, Edinburgh. “For a long time now, Fraser has taken over our kitchen to experiment with new recipes and to make up his jam orders. When he is in the kitchen none of the rest of us can get in, unless we are prepared to help. Even guests end up getting roped into putting labels on the jars.”