Horse Chestnut Bark – Cut Natural Dye & Tannin

Botanically: Aesculus hippocastanum L.

Dye Colour: Beige, Tan & Warm Brown | With Iron: Grey to Deep Grey-Brown

Horse Chestnut Bark is a lesser-known European natural dye material containing tannins, flavonoids and naturally occurring coumarin compounds.

Used alone, the bark generally produces soft beige, camel, tan and warm brown shades. When modified with a small amount of iron, these colours deepen into muted greys, charcoal browns and earthy grey-browns.

The bark can also be used as a tannin-rich preparation for cellulose fibres. However, as this is a whole botanical material rather than a standardised tannin extract, its strength will vary from batch to batch. For repeatable tannin mordanting, gallnut or tara may be more predictable.

Product Details

Suggested Quantity

For dyeing:

• Begin with 50–100% WOF

• Use up to 150% WOF for deeper shades

• Paler colours may be achieved with smaller quantities

For a tannin-rich cellulose preparation:

• Begin with approximately 20–30% WOF

• Test before processing a large or valuable piece

• Results may vary because this is not a standardised tannin extract

WOF means Weight of Fabric. For example, 100% WOF means using 100 g of dye material for 100 g of dry fabric.

Preparing the Dye Bath

1. Weigh the dry textile and calculate the required amount of bark.

2. Soak the bark in water for several hours or overnight.

3. Slowly bring to a simmer and extract for approximately one hour.

4. Allow the bark to cool in the extraction bath for a stronger liquor.

5. Strain the liquid before adding the textile.

6. The same bark may be extracted a second time and the two liquids combined.

Dyeing

Add the wetted, mordanted fibre to the strained dye bath.

Heat slowly and maintain at approximately 80–90°C for 45–60 minutes. Avoid boiling wool or silk. Allow the textile to cool in the bath for several hours or overnight if a deeper shade is required.

Rinse thoroughly and wash gently with a pH-neutral soap.

Mordanting

An alum mordant is recommended for wool and silk.

For cotton, linen and other cellulose fibres, use a suitable cellulose mordanting process. A separate tannin stage followed by an aluminium mordant or Alum/Soda Ash mordant, generally gives stronger and more durable results.

Horse Chestnut Bark may contribute tannin to a cellulose preparation, but its tannin strength is naturally variable and should be tested.

Iron Modification

A small amount of iron can transform the beige and brown shades into grey, charcoal or grey-brown.

Begin with approximately 1-3% WOF iron, increase only if necessary. Too much iron may dull the colour and can damage fibres over time, particularly wool and silk.

Iron may be added briefly after dyeing or used in a separate modifier bath.

Expected Results

Colours depend on the fibre, mordant, water quality, extraction time, season and the natural composition of the bark.

Possible results include:

• Soft beige

• Camel

• Tan

• Warm brown

• Grey-brown

• Muted grey

• Charcoal brown with iron

Natural dyes are living materials, and variations between batches are normal.

Colour Fastness

Expected Fastness: Medium

Mordanting generally improves wash and light fastness. Iron-modified shades may appear darker and more stable, but excessive iron should be avoided.

We recommend testing the dye on a sample before beginning a larger project.

The Plant

Horse chestnut is a large deciduous tree native to southeastern Europe and widely planted throughout Ireland, Britain and the rest of Europe.

The bark contains naturally occurring tannins and other plant compounds that can be extracted in water for natural dyeing. It has also been used historically in preparations outside textile dyeing, but this product is supplied exclusively as a craft and dye material.

Safety

• Sold for textile dyeing and craft use only

• Not intended for food, drink, cosmetic or medicinal use

• Do not ingest

• Keep away from children and animals

• Avoid inhaling dust or fine particles

• Wear gloves when handling concentrated dye baths and modifiers

• Use dedicated dyeing equipment

• Avoid prolonged skin or eye contact

• Work in a well-ventilated area

• Dispose of exhausted dye baths responsibly

Horse chestnut materials contain naturally occurring saponins, coumarins and other active plant compounds.

Storage

Store sealed in a cool, dry and dark place. Protect from moisture and direct sunlight.

A Note on Natural Materials

This is a minimally processed botanical product. The colour, particle size and dye strength may vary naturally between batches. Small pieces of other harmless plant matter may occasionally be present.