It took just two days for Denis Renty to raise £30,000 for his gluten-free craft beer company Van Bulck.

An entrepreneur for 20 years, the Belgian set a target of £15,000 on crowdfunding site Angels Den in May, with the aim of kick-starting his Tunbridge Wells-based firm with outside cash.

Before he knew it, he had been offered double the amount by two investors. Keen to take advantage of both of their contacts, he persuaded them to split the deal 50-50.

“We had a very good business plan and the product is very good,” said the ex-chef and sommelier.

“Craft beers are very in demand and we are unusual because it is the only gluten-free beer. Everything is organic.”

Mr Renty’s experience is not uncommon for start ups trying to raise some much-needed cash.

"If you are not confident in every angle there is no point, because an investor with a bit of knowledge will rip the ground from under your feet straight away...” - Van Bulck's Denis Renty

The innovation charity Nesta says £200m was raised through crowdfunding in 2012 and that it could raise as much as £15 billion a year in the future.

The investment has helped Van Bulck sell 25 pallets of its beer so far. Within weeks, Mr Renty is set to sign a contract worth £250,000 a year with the largest distributor of niche craft beers in the UK.

Yet he has some wise words for anyone who thinks the process is easy.

“Where a lot of people go wrong is a lack of preparation,” he said.

“I had two years of preparation. If you are not confident in every angle there is no point, because an investor with a bit of knowledge will rip the ground from under your feet straight away.”

One company that has struggled to raise money is velmai.

Its owners have spent the past seven years developing artificially intelligent chat robots, and aim to attract major investors by showing how their software can be applied to business on the website of a farm shop in Halling.

They decided to raise the cash to install the product using crowdfunding website Crowdcube.

Having put the pitch live on October 6, it has so far only attracted £5,600, out of a target of £300,000.

Under the rules of crowdfunding, if a business does not reach its target it does not get any of the money pledged.

Velmai director Tania Peitzker-Lingham, whose husband’s farm shop at Court Farm is set to host the new ‘chatbots’, briefly took the pitch down, concerned about brand damage after the money pledged remained at just over 1% of the target for so long.

Mrs Peitzker-Lingham put it live again within a day when investors began to call to ask where it had gone.

“We have to bear it as a start -up,” she said. “It is not as bad for us as it would be for an established company.

“Our situation is different because we are not like other companies on there.

“I assumed everyone knew that artificial intelligence could be online as well as in a robot.

“Public knowledge of it is not as mature as we thought.

“We thought people knew about Siri on their Apple phones. I am beginning to realise people are not getting it.”

A high-profile crowdfunding success was Tenterden winemaker Chapel Down, which raised just under £4 million on crowdfunding website Seedrs.

It persuaded nearly 1,500 individuals to invest within 21 days of a 60-day pitch, enabling the business to lease 400 acres of new vineyards and make more wine.

The firm became the first company on the stock market to use crowdfunding.

Chief executive Frazer Thompson said: “Crowdfunding is an exercise in high-quality marketing.

“If you are raising funds through city investors, you get an appointment and deliver a 15 to 20-minute pitch one to one.

“With crowdfunding you have a more traditional marketing proposition where your audience will not give you very much time.

“You have to draw people’s attention and have an idea which is easily summed up.

“You have 10 seconds to get your advert across, and it has got to be compelling.”