Chinese tea is in such demand in high-end luxury hotels such as the Astor Hotel in Tianjin that regular tea-making ceremonies are held in its Victorian Garden lobby.

The retired acoustic engineer continued to learn more about tea after he stopped working, and it was at a friend's request that he agreed to become a tea sommelier at the Ritz-Carlton to share his love of tea.

"Tea drinking is all about practice and experience - no diploma needed," he says.

He doesn't believe in hard sells, either.

"I don't even push my own children to drink. I let them discover on their own."

Ritz-Carlton's managing director David Wilson says Xie's expertise still "refreshes and inspires" after five years on the job. He's obviously happy with what tea master Xie is doing.

Indeed, Xie is living proof of the health benefits of drinking tea and says he's neither bothered by hypertension nor high levels of blood lipids. He credits his youthful vitality to drinking tea and advises his guests to "live life the way you appreciate a cup of tea".

For guests who appreciate his recommendations, he has a menu of special infusions with notes on the benefits.

Pu'er black tea on its own diffuses unwanted fat, and pu'er herbal tea with rose petals is for women who want a clear complexion.

Then there are the correct ways of drinking tea.

"You'll have to wait, focus. Let the tea steep, taste a little bitterness and finally work on the aftertaste that should be a little sweet," Xie says.

"It's just like life. You have to work and reflect on what you have gone through to get the essence and sweetness of life. It's especially true for those of us who have gone through decades of change."