What exactly is kombucha anyway?

'Fermented tea? Ooh no, I don't think so!' My friend scowled, sniffing the bottle of kombucha I'd passed under her nose suspiciously.

'Try it,' I laughed, practically tipping the lip of the drink into her mouth.

'Do you know what,' she added having sipped some of the cloudy ginger and lemon juice infused concoction, 'it's actually alright. Mmm. No, I quite like it.'

I guess that's a common reaction for Louise Avery of new East Anglian drinks company LA Brewery. Louise, who's gone into business with Archant 'Food Hero' William Kendall (formerly of The New Covent Garden Soup Co and Green and Black) says she's passionate about fermentation, and we shouldn't be scared of it. After all, where does beer come from? Or sourdough bread? Champagne even? All these things rely on fermentation to gain their complex flavour profiles. Without a second fermentation in the bottle, Champagne wouldn't be worth the time of day.

Kombucha – a combination of tea leaves, brewed with a 'lily pad' of bacteria known as a SCOBY- has become hot news on the world health food market, lauded for its (unproven) gut-healing properties. So trendy has it become, that predictions are the drink will be worth nearly 2 billion US dollars in the next couple of years.

Brands such as Equinox have already made waves in the UK, but with the support and knowledge of William and business partner Mark Palmer (formerly MD of Pret a Manger) Louise wants LA Brewery kombucha to be mass market. An alternative to icky, syrupy pub lemonade. In fact, she sees it sitting on pumps in restaurants and bars alongside beer – and that's already happening in London.

'I'm trying to get everyone I know into making kombucha,' the bubbly entrepreneur giggled, recalling the first time she tasted the beverage during a trip to Vermont with her boyfriend eight years ago. 'It was just sour, and a bit fizzy like Haribo sweets. It was like nothing I'd tasted before and I got addicted. I walked away with 2lts and downed it! I sort of fell in love with it.'

Back in London a short while later, working 9-5 as a studio manager, Louise had an epiphany. Feeling life was passing her by, she quit her job and returned to the Hebridean landscape of her childhood, where she worked in an organic weaving mill, foraging, weaving, cooking, and making batches of kombucha with the bounty of the Isle of Mull's hedgerows.

When a friend opened a restaurant in London, Louise was hailed back to help out and soon found herself experimenting on customers with the tea. 'It was the most beautiful time of my experimentation. I could bring out different flavours all the time, and combine making kombucha with my love of foraging. I'd make elderflower and peach, or hop flavoured.'

Louise was approached to write a book, and also by other restaurants to stock her kombucha, but things took a turn when Tomasina Miers (of Wahaca) a friend of her family, said she'd help by introducing Louise to William. His colleagues were so wowed by the drink that he drove down to Louise's tiny Hackney basement brewery (essentially a cupboard) and committed to helping her make it into a viable business.

'I'd known about kombucha for a long time,' William said. 'When I tried other examples I usually held my nose. When I tried Louise's it was delicious. It is even more delicious now. For 20 years or more I have been looking for drinks I can drink rather than alcohol. I love good beer and wine but I don't want to drink it all the time. The alternatives are usually water or a warm glass of sugary elderflower cordial. Kombucha ticks all my boxes. It is complex, very low in sugar, somewhat sour. I even find that a glass in the early evening completely removes any desire to open a bottle of wine.'

A factory was snatched up in East Anglia and LA Brewery took on its biggest customer, LEON, in the first six months, with demand for the drink such that a bigger brewery on the same site is currently in the pipeline.

Talking about the process behind the drink, Louise likens it to making a giant cup of tea. 'We infuse it lightly with tea leaves. I only use very high end, high altitude leaves which are produced without chemicals – and use a blend of 80% green tea and 20% black. The reason I use these teas is they create a honey, appley flavour and I wanted to make it as light as possible. It's about making it as balanced and accessible as I can.'

The SCOBY (good bacteria) is added to the brew, and stays in the tank for continuous fermentation to ensure consistency. And once the magic is completed (with five to 10 dominant strains of bacteria having created effervescence) a little sugar and natural flavourings are added. Currently lemongrass, lemon and ginger and strawberry and black pepper.

'The feedback's been amazing,' Louise enthuses. 'Definitely there's a lot of education to be done, but the restaurants working with us are loving it.'

Louise's book, Living Tea, is out now but due to be reprinted shortly as 'Kombucha'. Visit the LA Brewery website for stockists.