"We need to develop new process technologies, and HMF is a building block that can replace products like PET, a plastic used for soda bottles," he notes.

Even if the sour-sensing cells signal that the carbonation is sour, there are more elements to the process of actually tasting, say, soda water.

And trucks ply Shahe roads loaded with bags of synthetic soda ash, the product of a chemical process environmentalists forced out of the U.S. in 1985.