At Lee Kum Kee's Jiangmen Xinhui production base, a 137-year-old Hong Kong heritage brand is rewriting the rules of soy sauce making—with geothermal energy. But how does this sustainable system actually work?  

Tony Mok / VP of Global Manufacturing, Lee Kum Kee

The core ingredients in soy sauce production are soybeans and wheat flour. The traditional process involves multiple steps—steaming, koji cultivation, fermentation, filtration, and sterilization—all requiring precise heating and cooling.  

In 2015, this factory made history as the world's first soy sauce producer to tap into geothermal energy, installing a revolutionary heat pump system.  

Tony Mok:

During construction, we installed an underground closed-loop pipeline system. Water entering at 50°C exits at 24.3°C by leveraging the earth's stable temperature—dramatically cutting electricity use for heating and cooling.

But the innovation doesn't stop there. The factory also transforms waste into energy, starting with production wastewater.  

Tony Mok:

Our wastewater treatment includes anaerobic digestion to produce biogas. After desulfurization, we convert it to electricity. A constructed wetland park then naturally purifies the water before discharge.

By harnessing the earth's natural energy, Lee Kum Kee has slashed both energy consumption and emissions—proving tradition and technology can brew a better future.