How Sediment Affects Your Dyeing and the Importance of Proper Rinsing

Q: I am dyeing in a ferrous vat and got sediment from the bottom of the vat on my piece. Is that bad? What should I do?

A: A ferrous vat has an iron-rich sediment which collects at the bottom of the vat. If you’ve gotten any of this sediment on your piece make sure you rinse it thoroughly in fresh flowing water before it goes back into the vat for its next dip. If the sediment is resting on your piece when you dip into the vat the indigo pigment will adhere to the sediment and not the fabric. It functions like a resist on the fabric and when you finally wash the piece, you’ll rinse all of the indigo off back to the dip where the piece first hit the sediment. You can’t over-rinse between dips!

Contact with the sediment can also stain your pieces with a mottled brown/green. To remove the staining, wash the pieces with excess detergent in hot water (bar soap works great) until the water rinses clean.

The deeper your vat container is the easier it is to avoid the sediment. If you need to dye in a small vat but have pieces that are large in size you can try putting some sort of bag/basket/strainer in the vat secured to the top of the container so that your pieces literally cannot touch the sediment. Also, make sure to not stir the vat beforehand on the same day it is used to dye so that the sediment has time to settle.