Quotes of the Day

You can't help but think of Willy Wonka when you meet Tsang Heh-kwan. While walking around her factory in Hong Kong's New Territories, the 80-year-old giggles as she offers samples of a candy product she's developing. The subtly sweet ginger confectionery is a delight, and Tsang — hale and lively — declares that she has finally perfected the formula that prevents it from sticking to teeth.

Candy may be in the pipeline for her 35-year-old company, Fu Kee Food Co. But gourmet sauces sold under the brand name Yuan's, www.i-ho-yuan.com, are what have earned Tsang a fanatical fan base from Hong Kong to Amsterdam. A 125-ml bottle of Yuan's soy sauce retails for $21 — the most expensive in the world, Tsang brags. "Why is it so expensive?" she asks. "Because it's an ancient Chinese recipe, and no one can steal it because it's in my head."

A trained biochemist, Tsang moved to Hong Kong from her native Guangzhou in the 1950s and soon became an apprentice to one of the city's last traditional soy-sauce masters. In 1974, she struck out on her own and founded Fu Kee with the help of just two employees. The company now sells a range of Yuan's sauces in England, Australia and several Asian countries, but amazingly, the original trio of employees continues to handle all aspects of the operation. Tsang travels 90 minutes by bus to get to the factory every day, where she still concocts recipes, monitors production, manages sales and marketing and handles the books. Her two assistants are responsible for production, bottling, packaging and factory maintenance. "They are like my kids and I'm like their mom," she says of the two men, now in their 50s.

To tour her factory today is to witness one of the last food operations in Hong Kong that still follows time-honored methods. Rows of massive ceramic vats command center stage on the factory floor. In them, blackened soybeans, salt and a dash of wheat flour ferment for more than a year before Tsang deems the process complete. The rich, smoky, preservative-free sauce is thicker and less salty than its competitors. Yuan's oyster sauce, which sells for $24 for 250 ml and tastes like a blast of fresh oysters, is even more impressive.

Despite its heritage, the factory's future is anything but certain. Tsang's two sons aren't interested in inheriting the family business, and her employees don't have a command of the science behind the sauces. "If I die," says Tsang, "no one will make this kind of soy sauce anymore." Just as well she has plenty of life left in her yet.

• Ling Woo Liu
• Yuan's gourmet sauces have a fanatical fanbase from Hong Kong to Amsterdam