Raw silk must be refined before it can be woven into satin.
Tips
culture
生 here means 'raw / unprocessed', as in 生肉 (shēngròu 'raw meat'). 生丝 is silk straight off the cocoon, still coated in sericin gum; once degummed and softened it becomes 熟丝 (shúsī 'cooked / finished silk').
