This method began in the Yuan Dynasty. It is said that there was a businessman named Huang in Nan 'an, Fujian Province, who opened a small sugar shop. One day, the wall of the sugar shop collapsed, and the yellow mud in the wall covered the brown sugar he made. When removing the yellow mud, he found that the brown sugar covered with yellow mud turned white, so he repeatedly tried and proved that covering yellow mud on the brown sugar could make the brown sugar turn white, so he used this.

To put it simply, the most important thing in making white sugar is to make brown sugar white. In history, besides yellow mud, lime, white stone and duck egg white were used to clean brown sugar juice.

Extended information

Because sugar is so precious, we ancient people began to learn all kinds of sugar-making techniques. We learned from Egypt and Persia. In the period of Emperor Taizong, Wang Xuance was sent to India to learn how to make white sugar. Of course, he not only "destroyed one country by one person", but more importantly, he brought the method of sucrose back to the Tang Dynasty. Since then, the level of sugar-making technology in China has been greatly improved.

After the Song and Yuan Dynasties, China continued to learn foreign sugar-making technology. The Travels of Marco Polo recorded that several people from Babylon taught China to refine white sugar with wood ash. It was through continuous efforts that the "yellow mud and sugar drenching method" was finally born in the Ming Dynasty, and human beings could finally produce today's white sugar.