Sumac belongs to the group of almost colourless gallotannins, alongside oak galls and tara. This makes it one of the most important tannins for natural dyeing, especially in the ‘galling’ stage of cellulose mordanting before applying alum. Its high tannin content ensures strong binding of mordants to fibres, resulting in brighter, more durable colours.

Historical Note
Sumac was a staple in the dye workshops of the 17th and 18th centuries. Master dyers prized it for its reliability, and it is frequently mentioned in historic recipe books as a foundation step for mordanting cloth. Its role as a “base coat” for mordants gave it a reputation as one of the quiet workhorses of the dye house.

Active Components
Hydrolysable tannins (up to 30%).

CI Colour Name
Not applicable (used primarily as a tannin/mordant assistant).

Notes

• Suitable for all textiles (protein and cellulose).
• Especially effective for cellulose fibres, creating a strong tannin-alum bond.