Peng Crystal Silk Sweet Potato Powder is a specialty of Pengshui County, Chongqing.

In Pengshui, sweet potatoes are called sweet potatoes, so the powder made from sweet potatoes is called sweet potato powder.

To obtain high-quality crystal sweet potato powder, one must first put effort into selecting sweet potatoes. Zeng Qinglu, who has lived in Yushan for a long time, is a scholar who has been studying the local cultural history. In an article introducing Yushan Jingsi Tiao powder, he wrote: "In terms of variety, it is necessary to choose Baihua Tiao, because Baihua Tiao has a large yield, high flour yield and sweetness; in terms of region, it is necessary to choose red Tiao produced from sticky loess with sufficient light and nutrient conditions, because the red Tiao cultivated under such light and nutrient conditions is large, uniform, smooth and compact, suitable for processing

In fact, people engaged in the processing of sweet potato flour have not stopped exploring higher quality sweet potatoes. Deng Xinbo, a staff member of the Longxu Crystal Silk Sweet Potato Powder Professional Cooperative, introduced to the author that they have now chosen Yushu Wang, which has higher production and powder yield, with a starch content of up to 20%.

There are agricultural proverbs that say, 'When the elm is full, plant sweet potatoes' and' When the oriole leaves, produce sweet potatoes'. Every autumn, sweet potatoes pile up like mountains in front of the processing plant. The sweet potatoes that come here have red and white skin, uniform size, and are all excellent raw materials for making glutinous rice flour.

The first process is to give the sweet potatoes a "bath". Trucks of sweet potatoes are poured into the cleaning machine until there is no sludge on the surface before being sent to the next process - crushing. Don't underestimate the process of cleaning sweet potatoes. The cleaner you wash them, the more crystal clear the color of the sweet potato powder will be.

After crushing, the residue without nutritional components is filtered out, and the remaining substances are transported to the sedimentation tank for sedimentation.

During the precipitation process, impurities and oil content in the sweet potato skin will float to the surface. This yellow substance is commonly known as "oil powder". The sweet potato powder made from starch without removing the oil powder is dark and not transparent enough. People usually remove the oil powder, so that the sweet potato powder is crystal clear.

After 24 hours of precipitation, the water is poured out, and the remaining starch is called water powder by the locals. Water powder is as white as cheese and shaped like sheep fat.

The processes of cleaning, crushing, filtering, settling, and removing oil powder can all be assisted by machines, but when it comes to the core step of making crystal silk sweet potato powder - "wave sweet potato powder", it has to rely on manual labor.

The word 'lang' is actually a homophone, and Deng Xinbo said he didn't know how to write it. On the contrary, in the Pengshui dialect, everyone pronounces it this way. Before "Langtiao Powder", workers scooped out a bucket of starch from the sedimentation tank, added water to the mixer, and stirred it to make starch slurry. The dryness and humidity of starch slurry are particularly important: if it is too dry, the waves will not move, and the resulting powder is prone to breakage; Too wet, the powder won't dry, it's easy to stick.

The tool for "Lang Tiao Fen" is a homemade Lang basin, which is more accurately called a box than a basin. The wave basin is made of aluminum, rectangular, chest length, and has a fixed size. Every time there is a wave, only scoop one spoonful of starch slurry, so that the size of the starch skin produced by the wave is consistent. Boil a pot of water in a large iron pot commonly used in rural areas, and feel it with your hands. When the water becomes slightly hot, you can start to "wave". The workers hold wave basins and place them on the water surface, gently shaking them back and forth. The starch slurry "crawls" up to the bottom of the basin as it sways, gradually turning from white to transparent. Skilled hands produce even thickness of the pink skin that comes out of the waves. When the noodles are almost dry, sink the basin to the bottom of the water and cook for a minute. After cooking, take it out and a pink skin is ready.

After the powder skin cools down, it continues to peel. There is also a trick to peeling the dough. Before applying the dough, brush a layer of vegetable oil on the bottom of the bowl. When peeling, slowly pull it from both sides towards the middle, and the dough will hang upside down on the bamboo pole. After one or two days of air drying, cut the pink skin into shreds and air dry it completely.

When it comes to the drying process, it is also the most beautiful moment for Tiao Fen. The pink skin on the drying pole is shiny and thin, with a good luster; After being cut into shreds, it looks like a beautiful woman's hair, smooth like a waterfall.

Sweet potatoes are originally coarse grains and seem to be off the charts. However, many people do not know that as early as the Qianlong period, the people in the Pengshui area changed the fate of sweet potatoes. They discarded their dregs and used sweet potatoes to make the "treasure of the mountains" - crystal silk sweet potato powder.