Parts used: bark
Color range: browns, fawns, pinks, reds
Mordant: none, alum, iron
Light fastness: good
WOF: 100-200%
Fermentation dyeing: yes
Hot dyeing: yes
Low Impact Method: no
 
Always soak bark and roots overnight before heating. Use a dye bag when dyeing wool or the bits will get stuck in the fibers. Heat slowly to below a boil, boiling may dull colors. No mordant is needed but alum will intensify the dye results.  A bit of soda ash will give deeper pinks.
 
Our birch bark is a by-product of renewable forests planted for the furniture industry.
 
Birch bark is a wonderful folk dye and great for yarns. 
 
You will need:
Fresh or dried birch bark
Mordanted (usually with alum) fabric to be dyed (preferably made of natural fibers like cotton, silk, or wool)
Large pot for heating bark
Water
Instructions:
Collect or purchase birch bark. You'll need approximately 100-200% WOF of dried birch bark.
If the bark is fresh, dry it thoroughly in a cool, dark place before use.
Place the birch bark in a large pot and add enough cold water to cover the bark byseveral inches and soak the bark pieces overnight.
Heat the water to just below a boil, then reduce the heat and simmer for 1-2 hours,stirring occasionally. Strain the bark out of the water, you can reuse them for a following exhaust bath by repeating the process of soaking and heating)
Add your mordanted fabric to the dye bath and bring the water back up to a simmer. Continue simmering for 1-2 hours, stirring occasionally, or until you achieve the desired color.
Remove the fabric from the dye bath and rinse it thoroughly in cool water until the water runs clear. You can also use a gentle detergent to wash the fabric if desired.
Hang the fabric to dry, out of direct sunlight.
Keep in mind that the exact shade of your dye will depend on the specific type of birch bark, its age, and the length of time you simmer it. You may need to experiment with different batches to achieve your desired color. Different mordantswill produce different shades.