Most of us have been there. The booze is flowing, the socialising is buzzing, everyone has a tipple in hand. But you’re the driver… or you’re pregnant, or you’re on a diet, or you’ve a big meeting at 9am, or alcohol gives you a headache. Or you just want to be free for a while of the pressure to conform to a drinking norm. Or you’re among the 30 per cent of adults who simply like the idea of staying sober.

So what can you do? Join the kids with a coke or orange juice?

David Begg, a Chalfont St Giles entrepreneur, is familiar with the problem. “A few years ago I realised I no longer found much pleasure in drinking wine or beer. Alcohol just didn’t agree with me any longer.”

David’s wife is French, they have a home in Burgundy, they’d always loved eating good food with friends with wine to match. “There was now a gap that a soft drink simply didn’t fill. I missed the complexity of flavours of wine, the theatre of drinking it.”

Then came something of an epiphany. David recalls: “Four years ago a friend offered me a glass of kombucha which he had brewed at home. It was a revelation. I could not believe this fascinating drink was just 0.5 per cent alcohol.”

This was David’s first taste of kombucha, a fermented tea drink that has been brewed in the Far East for centuries and was having its moment in the spotlight in the US (where it’s a $1bn market, thanks to a new interest in fermented foods for gut health).

David took home some of his friend’s culture and brewed up some silver needle tea leaves he’d brought back from holiday. “It was better than any champagne I’d tasted, with notes of rose, vanilla and almond. It was also quite different from my friend’s brew, which was made with black oolong tea giving robust flavours more like a beer.

“I thought: if these two teas can produce fermented drinks of such varied complexity, what else could we do?”

So began a journey of discovery, experimenting in the family kitchen with scores of tea varieties. He read up on microbiology, spoke to scientists, visited winemakers and brewers to understand the processes. The end result was a new business: Real Kombucha. Four years on, Real Kombucha is served in almost 50 Michelin-starred restaurants, including the Fat Duck, Le Manoir and the Hand & Flowers, and in scores of high-end restaurants and bars. At L’Enclume, it’s served in champagne flutes as their welcome drink.

What’s the appeal? “The flavours are as complex as a wine, it pours like an adult drink, it keeps the party fun. It has much less sugar, with 42 calories in a glass compared with 250 calories for most wines.”

While other kombuchas on the market focused on its microbial properties as a gut-health drink, adding flavourings to a simple base, David’s aim was a sophisticated substitute for wine, free of any added flavours.

He ended up with three Real Kombucha varieties, and I join him at his brewhouse in farm buildings near Wendover for a tasting. First, Royal Flush, brewed from silver needle tea from a single tea garden. Amazingly delicate yet delightfully full of fruity notes of peach and rhubarb, served sparkling in a flute this would be a delicious drink to sip at a party or wedding. My favourite.

Next, Dragonwell, a pan-fried green leaf from China giving notes of straw and hay, green tea and grapefruit, which David compares to a dry sauvignon blanc. Great well chilled on a summer’s day for easy drinking.

For a more robust drink in place of red wine, Smokehouse uses a full-bodied black tea with notes of apple and caramel, good with red and BBQ meats.

All are very lightly carbonated and because the culture is live, they are best drunk within six months.

The brew receives as much care as any fine wine, with David and his team sourcing Chiltern water from the local aquifer. I’m shown the massive ‘teapot’ in which the tea is brewed before moving into one of nine huge stainless steel fermentation tanks, specially designed by the team, where it stays for two to eight weeks. I also get a peep into the lab and the ‘motherhouse’ where the precious yeast-and-bacteria culture is cosseted.

With the party season approaching, it seems David has found a viable option for those who want something adult but non-alcoholic on occasions. “I’m certainly not anti alcohol,” he explains, “I’m anti its habitual use and the peer pressure that comes from it. This fills the space when you go to the pub and don’t want a beer.” And cutting down on alcohol, he adds, is a massive trend among the 16 to 24 age group.

Most of the bottles of Real Kombucha are delivered to high-end restaurants, hotels and bars, but it is also available at a few outlets including Peterley Farm Shop, The Hatchery and Budgens, or it can be ordered online at realkombucha.co.uk.