By Mary Katherine Smith

For more than 130 years, Heritage Soy Sauce Factory has produced its soy sauce the old-fashioned way, where the fermentation process may take up to two years.

Many of its competitors have succumbed to modernity, where the soy sauce is artificially hydrolyzed, commercially produced and fermented in machine-controlled environments, in a process that takes just 20 days.

For Zhang Huizhong, Heritage's general manager, he is just following his father's footsteps. It is the difference between 20 days and two years that sets Zhang's product above others.

Not only is the soy sauce better tasting, he argues, it's also better for health because there are no preservatives like those found in mass-produced sauces.

It all starts with a humble bean. Zhang says that the soybeans used in their sauce come from Northeast China and have no preservatives, additives or enhancements.

The only other main ingredient is wheat, used to add color and sweetness to the sauce, and a natural yeast starter to aid the fermentation process.

This traditional, labor-intensive way of producing one of China's most sought-after sauce has brought national brand recognition to Heritage.

Already a "time honored brand in China", in 2008 the factory was awarded the Intangible Cultural Heritage tag, the only one in the soy sauce making industry, says Zhang.

Government and related officials have taken noticed of the factory's effort and it has been commissioned to produce more items. But despite the awards and government support, the factory has to overcome many hurdles, the biggest being enough money for expansion.

Another problem is attracting enough new blood to learn the skills. Zhang explains why the life of an artisan soy sauce maker may not be attractive to the young: laborious working conditions, a low salary and resistance from their families.

Their 2008 award, however, has helped raise awareness for the factory and more people are now taking an interest in the factory and its soy sauce.

"After we received the Intangible Cultural Heritage award, more and more people want to joinour factory," he says, adding that they have been able to attract some new workers from around the country.

The sauce is produced in small quantities and is only released at certain times of the year at the Shanghai No 1 Food Store along busy Nanjing Road. With the limited quantities, the price tag is about 30 yuan ($5) per bottle, but it still has a steady stream of regular buyers. Zhang says 70 to 80 percent of buyers are repeat customers.