Early methods of brine salt production involved digging large pits in the earth (other parts of China used the evaporation method). Later methods involved very innovative drilling and retrieval methods. An unexpected byproduct of the drilling and resulting wells was natural gas. Since natural gas didn't have the uses it does today, it was channeled into pipes and primarily used onsite to boil the brine and extract the salt. The salt Zigong produced was very rich in taste and was served to the Emperor of China as a tribute. The people of Zigong believe its taste to be superior to the popular French sea salts such as Fleur de sel.