While on a trip to Shilou, in Yunlin County, Taiwan in mid-July, I savored an opportunity to learn the traditional method of producing (black soybean) soy sauce. Shilou is an old town in an agricultural area of Taiwan, and is home toWuan Chuang Food. Wuan Chuang Food was established in 1909, during the Japanese Colonial era, and its current facilities sit on its original site. The company is perhaps the last manufacturer that produces soy sauce products from black soybeans with traditional methods that date back hundreds of years.
After sampling preserved soy sauce eggs at the gift shop next door, I entered the Wuan Chuang center for a tour. The tour guide showed display photos showing the history of the company. She explained exhibits describing the entire brewing process, and showed the tools that were used. The guide explained how the Japanese used yellow soy beans using a different process. In a bamboo tray were black beans growing mold on them. In the back of the building, in a small courtyard stood about 80 large brown clay urns covered with clay lids. She opened a lid revealing a top layer of salt about 2 inches thick covering the soy sauce underneath that was fermenting.
From what I learned from the tour, this is how black bean soy sauce is made:
1) Black soy beans are harvested and washed.
2) The black soy beans are steamed and placed on round bamboo trays to cool off.
3) The black soy beans remain in the bamboo trays for 7 days. During that time, a thick layer of mold (aspergillus oryzae and aspergillus soyae) grows on the soybeans. The mold has also permeated inside the soybeans.
4) The black soybeans are washed again and mixed with salt and some water.
5) This mixture is placed into large clay urns and sealed airtight with a layer of raw salt. A clay lid is placed on top. The urns stand outside, fermenting the beans for 180 days.
6) The fermented black soy paste is poured out of the urns and is strained and the particulates are removed. The soy paste may be bottled, or water may be added to make soy sauce.
Most soy sauce manufacturers in Asia use yellow soy beans. Taiwan has a few producers that use black beans, including Wuan Chuang, O’Long, TaTung, and RueiChun. Wuan Chuang celebrated its 100th anniversary last year, with a special urn of black bean soy sauce being brewed by the President of Taiwan.
