De-gumming

The process by which the gum or sericin is removed from raw silk. The extent to which the gum is removed varies with the type of silk yam. In Ecru Silk only about 5% of the gum is removed. In Souple or Supple Silk about 10-15% of gum is removed. In Cuite or boiled-off silk the gum is almost completely removed. It is removed by boiling the silk in a mildly alkaline solution. This process, called de-gumming, or ‘boiling off’, leaves the silk soft and lustrous, but it can reduce the weight of the silk by as much as 25-30%.