A small, Essex-based milkshake producer is celebrating a contract that will see its sales boosted by 100 per cent in the coming months. Following a brand revamp, Shaken Udder milkshakes will be hitting the chiller cabinets of 200 Sainsbury's stores across the country this week in a deal that owner Jodie Farran says will “double our business overnight.”

Acceptance among the High Street hierarchy represents a remarkable shift in fortunes for a business forged in the mud of Glastonbury and other music festivals.

Farran caught the entrepreneurial spirit at university. In 2003 she and Andrew Howie hit on the milkshake recipe and started peddling their product around Britain’s music festivals and also slogged round the food show circuit.

It was almost five years before the product had its first big breakthrough and landed on the shelves of Harvey Nichols.

Now the Sainsbury’s contract is a game-changer for Shaken Udder, still based on an Essex farm.

“This is such an exciting contract,” said Farran, who admits the deal has been a long time coming. “We've had to work really hard to ensure our milkshakes are right for the multiples and now we can't wait to see them on the shelf in Sainsbury's stores all around the UK – it's fantastic to know that even more people will have a chance to try them.

“We are still only a very small business so a deal like this will make such a huge difference to us. It's also a brilliant morale-boost for the whole team.”

Shaken Udder can now reel off a long list of household names stocking its milkshakes – Sainsbury's, Ocado, Waitrose, regional Co-op stores, Fortnum & Mason, Harrods, Wholefoods, Harvey Nichols and Selfridges.

Farran believes the long haul has been worth it. She said: “My family have always run their own businesses and I started working for my dad when I was 11 making teas and hoovering. As I grew up he ran about six different ventures that I worked for, from shoe shops to a cosmetic factory – it all gave me a great entrepreneurial spirit and it just seemed normal for me to start a business myself. In fact, it was more daunting thinking about working for someone else.

“Andrew Howie's family are farmers so there is a really strong work ethic there, too. We believed straight away that we had a great product so we jumped straight in and got our heads down. We were naive about what it all involved, but I think if we'd considered it too much, we'd never have done it.

“We worked really hard. The first year we worked the festivals alongside our day jobs. Andrew's brother had started processing his own sausages and bacon so when we weren't doing festivals we worked for him. We saved every penny and all the money we earned was used to grow Shaken Udder. In two years we had gone from one catering unit to four and a team of 25 people in the summer months.”

For the first three years around the festivals the partners didn’t see one band: “You are there to earn a living and with our season being from May to September, every day at an event counts.”

Farran recalls the lowpoint of Glastonbury 2007. “We arrived to a beautiful field of green; our pitch was at the bottom of the hill and with a lot of rain forecast we knew if it rained we'd be flooded. And rain it did – all weekend. We ended up in a river of water and mud right up to the door of the unit and had to build a bridge of straw so customers could get to us! It took three tractors to tow us out when we came to leave.”

Now the partners are raising a glass of milkshake to their Sainsburys success and no doubt proffering a suitable toast: “Here’s mud in your eye!”

• Photograph shows:  Jodie Farran with Andrew Howie