In 1990 the US tea industry, starting to rebound from a slump in tea drinking that dated back to the second world war, was worth US$1.84 billion. By 2006, strongly flavoured by mass marketing campaigns linking tea drinking and health, this figure had jumped to US$6.50 billion. A leap to US$10 billion is predicted by 2010.

Represented in this surge is 'tea' in all shapes and styles. There are herbal concoctions, fruity tea beverages, Asian bubble teas and sweet'n'spicy chais. Much of what is drunk as tea these days is cold and comes in a bottle - alternatively it is flavoured and sold in bags.

And then there is real tea - which is where Mr Fong comes in. He was the frontrunner and today is the superstar role model - the elder among a growing band of tea importers in the US who are riding the crest of the booming industry. As well as entrepreneur, he is also the teacher tutoring eager westerners that fine tea is analogous to fine wine.

Tea, for Mr Fong, embodies all the best of China's elegance, refinement and history - things few westerners think about when they see the 'Made in China' stamp on cheap goods. Of the 8,000 tea enthusiasts he has on his mailing list, only 100 are Chinese.

If Mr Fong appears to have the zeal of a true convert, it's because he is one. At age 21 he could speak little Cantonese, no Putonghua and had given little thought to his roots.

Now he is fluent in both Cantonese and Putonghua. He and his family - wife Grace, originally from Beijing, and daughters aged 18 and 10 - speak exclusively Putonghua at home in Lafayette, a small high-income city east of San Francisco that boasts one of the best school systems in California.

It is clear he didn't learn about tea from his family. In fact, it sounds like his mother made tea like a Texan cowboy. 'She would grab a handful, shove it in a thermos, pour in water and if it took six months to finish that thermos, my god you finished that thermos before any more water went in,' he said.

Mr Fong, a genial, likeable man with laser-like focus that would befit an ordained Taoist priest - which he is - laughs at the memory.

He was born in Wan Chai. 'Later we moved to Kowloon side, to Yau Ma Tei,' he added. His only exposure to gongfu tea before age 21 was while squatting with day labourers around a piece of cardboard near a small food stand on his way to kindergarten.

Mr Fong's mother was a housewife and his father, a contractor. 'We were probably very close to poverty level,' he said.

His dad's brother, on a visit from San Francisco, urged Mr Fong's father and older brother to return with him. The rest of the family followed later - in 1970 when Mr Fong was 13.

'My uncle put up the money for the plane tickets and rented the apartment for us and after everyone got here, in three months we paid him back. Two days after I got to this country, my uncle got me a paper route.

'I spoke no English - but everyone worked in the family. All seven of us. My parents instilled that kind of work ethic. You want something, you work for it,' he laughs.

By age 21 he had his own business - an auto repair and towing service. 'I was making pretty good money - but every Friday people would want to kill you because you'd towed their cars. It gets very trying after a while. Working seven days a week, I didn't have a life.'

He decided to come to Hong Kong for a one-month holiday. Had he been a tea drinker and read the leaves, he'd have known this trip would transform his life.

'One day I decided to go to this old district I'd heard about as a child, Sheung Wan, where there were shops that sold dried seafood, tea - things like that.'

Soon as he got there, his nose led him to a tea shop. 'It was like someone grabbed me by the neck and dragged me in. If you've ever smelled tea being roasted, you'll know how tremendous it is,' he said.

'Inside, an older gentleman sat me down and made me tea [gongfu style]. After that, I went back every day and by the end of the month, I had visited all the tea shops.'

Mr Fong went to Hong Kong with a suitcase of clothes. He returned to San Francisco with the clothes on his back and two suitcases, both filled with tea.

That was it. His love affair with tea and deep appreciation for its cultural context had begun. By 1992 Mr Fong was in the import-export business - 'losing money most of the time - except for the tea I sold to a company that wholesaled to all the Chinese restaurants in San Francisco. We were importing 10 containers a year.

'Because I sold tea, people would ask me where they could buy tea - something better than the Chinatown version.'

It was then that he resolved to establish a real tea shop where people could drink, buy and learn about tea.

North Beach in San Francisco is a neighbourhood best known for its Italian restaurants, beatnik-era hangouts, bars and nightclubs. The intersection where Broadway crosses Columbus Avenue is its heart.

One side of this busy junction supports a cluster of neon-flaunting strip clubs. The other side flows seamlessly into San Francisco's Chinatown. A short two-block walk takes you to Powell Street and Fong's Imperial Tea Court.

When he opened 13 years ago, nobody knew interest in tea would skyrocket. The tea house was a risk - and an expensive one.

To transform what had been a sewing factory into an elegant traditional tea house, he knew everything must come from China. The goods arrived in a container.

'The hand-rubbed rosewood Ming dynasty-design tables and chairs, the nails, the glue, the paint - everything is from China,' he said as he prepared his signature Tieguanyin (Iron Buddha) tea gongfu-style. The monkey-picked oolong sells for US$220 a pound (0.45kg). 'It took me a year to sell 10 pounds when I first made this. Today we sell 10 to 15 pounds a week.'

His top of the line Dragonwell sells for US$480 a pound and every year there is a waiting list.

The first few months he opened, 'we were doing a few dollars a day', he said. Today he has his original tea house. He opened a second three years ago in San Francisco's trendy, upscale Ferry Plaza - a highly sought-after location favoured by locals and tourists.

Then there is his Berkeley tea house-cum-restaurant - two doors away from California's arguably most famous restaurant, Chez Panisse, in a neighbourhood facetiously called 'the gourmet ghetto' for its plethora of superior restaurants and the area's affluence. His wife created the recipes for the menu of organic northern-style Chinese food.

Mr Fong also has a 16,000 sq ft warehouse in an industrial area near San Francisco where he stores his 200-plus varieties of tea and the teapots he imports - some custom-made - from the historic pottery workshops of Yixing in Jiangsu province .

He also roasts speciality teas and conducts business in a private tea room furnished with Chinese antiques. He owns a tea factory in Fuzhou , where he makes his jasmine tea. He has custom growers - contract farmers - in Hangzhou and in Fujian province .

He travels to the mainland for extended periods at least four times a year and on any visit will crisscross the country up to 15 times by air.

Tea, he says, is a gentleman's business - but not for 'the lightweight'. On the one hand you develop relationships and do deals based on your word. But then there are the things you can't control. 'Frost can wipe out your harvest and there's nothing you can do.'

He built his business on the principles of tradition and quality. You cannot hope to understand a region's tea, he says, without understanding its people 'what they eat, how they talk, their painting style, the history and traditions, the calligraphy, the foliage on the mountain'. This is his way with tea.

When Mr Fong created his first tea house, he flew in six artisans from the mainland for a month to assemble the interior. Then he and his wife spent a year redoing the job.

'We crawled every inch of this floor. They laid the tiles with mortar instead of glue and didn't wipe the edges so the concrete dried and we had to scrape it off.'

Mr Fong had selected the marble tiles on the mainland. 'I believe the Chinese philosophy that the foundation is most important and you always work from the ground up.'

He sees this principal as the main cultural difference between how Chinese and Americans do business. 'Americans want things right now. They fly in at 3 and want to sign a contract at 5. With Chinese, everything is from the ground up. You need a solid foundation to build a business, a relationship.'