Acacia Extract – Black Wattle Tannin
Acacia mearnsii De Wild. · Condensed Tannin Extract
Acacia Extract is a concentrated botanical extract produced from the bark of Black Acacia, also known as Black Wattle or Mimosa.
Containing approximately 60–65% condensed tannins, it can be used as a warm beige-to-brown dye, a tannin treatment for cellulose fibres and a base for greys and dark shades with iron.
Unlike pale tannins such as Oak Gall or Tara, Acacia Extract contributes a noticeable warm beige-brown background. This can add depth beneath stronger colours but may influence pale or delicate shades.
Colour samples
The two colour samples show Acacia Extract applied to cotton fabric under different preparation conditions:
- First sample, left: Dyed on mordanted fabric
- Second sample, right: Dyed without mordant
The mordanted sample produced a considerably deeper rust-brown, while the unmordanted sample remained a much paler beige.
The photographs demonstrate the effect of fibre preparation rather than guaranteeing an exact shade. Results will vary with fibre, mordanting method, extract quantity, water chemistry and dyeing process.
At a glance
| Feature | Details |
|---|---|
| Product | Acacia Extract |
| Botanical name | Acacia mearnsii De Wild. |
| Common names | Black Acacia, Black Wattle, Mimosa |
| Plant part | Bark |
| Form | Concentrated powdered extract |
| Main constituents | Approximately 60–65% condensed tannins |
| Other constituents | Flavonoids, including chalcones |
| Colours | Beige, tan, warm brown, grey and brown-black |
| Main fibres | Cotton, linen, hemp and other cellulose fibres |
| Other fibres | Wool and silk may also be dyed |
| Material | Concentrated extract |
Suggested quantities
| Use | Acacia Extract |
|---|---|
| Light beige | 5–10% WOF |
| Medium tan or brown | 10–15% WOF |
| Stronger brown | 15–20% WOF |
| Cellulose tannin treatment | Begin with 10–15% WOF |
| Grey or dark shade with iron | 15–20% WOF Acacia, followed by carefully measured iron |
WOF means weight of dry fibre.
For example, 10% WOF means 10g Acacia Extract for every 100g of dry fibre.
These quantities are starting points. Results depend on the fibre, preparation, mordant, water chemistry, pH and dyeing method.
Cellulose tannin treatment
Acacia Extract may be used as the first stage of a two-step cellulose mordanting process.
The tannin initially attaches to cotton, linen or hemp through affinity. It must then be followed by an appropriate aluminium treatment to form insoluble tannates required for effective mordanting.
Suitable second stages include:
- Alum combined with soda ash
- Aluminium acetate
- Aluminium lactate
Tannin alone is not a complete cellulose mordant. Equally, the aluminium stage alone does not replace the tannin stage when following this two-step method.
Suggested tannin treatment
- Scour the cellulose fibre thoroughly.
- Dissolve 10–15% WOF Acacia Extract in warm water.
- Prepare a bath at approximately 40–50°C.
- Add the dissolved extract and stir thoroughly.
- Add the wetted fibre and immerse it fully.
- Leave for one to two hours or longer, moving the fibre occasionally.
- Remove wearing gloves and squeeze or spin out the excess liquid.
- Rinse very lightly, if at all, because the tannin is initially held only by affinity.
- Move directly to the chosen aluminium treatment without allowing the fibre to dry.
Acacia leaves a warm beige or tan base. Choose a paler tannin where maintaining a lighter background is important.
Find the complete cellulose mordanting method here:
How to Mordant Linen and Cotton Fabrics Successfully
Using Acacia as a dye
Acacia Extract can also be used as a warm botanical dye in its own right.
- Scour and prepare the fibre appropriately.
- Make a smooth paste with the measured extract and a little warm water.
- Add the paste to the dye bath and stir thoroughly.
- Add the pre-wetted fibre.
- Raise the bath gradually to approximately 80–85°C.
- Hold for 45–60 minutes, moving the fibre regularly.
- Allow it to cool in the bath for a deeper shade.
- Rinse thoroughly and wash gently.
Acacia produces beige, tan and warm-brown shades without iron. Appropriate mordanting generally improves depth, consistency and durability.
Modifying with iron
Acacia’s condensed tannins react strongly with iron, shifting beige and brown towards grey, charcoal and brown-black.
For a controlled and more fibre-friendly treatment, we prefer freshly prepared ferrous acetate.
Begin with:
1% iron WOF
Use gentle warmth and apply the iron directly near the end of the dye bath. Immerse for up to 10 minutes, using less time for delicate fibres. Remove and aerate for approximately 10 minutes before assessing the colour.
Repeat the immersion and aeration cycle if required. For most work, remain within 1–3% iron WOF.
Do not add excessive iron in pursuit of black. Excess iron can damage fibres. For richer dark shades, combine Acacia with another tannin and a colour source such as Logwood, then modify carefully with iron.
Possible combinations include:
- Acacia and iron for grey or charcoal
- Acacia, Tara and iron for layered dark shades
- Acacia, Logwood and iron for brown-black or near-black
- Acacia and Madder for rust and brown-red
- Indigo followed by Acacia for green, olive or muted blue-green
When layering with indigo, apply the indigo first, rinse thoroughly and follow with Acacia. This helps prevent contamination of the indigo vat.
Working with protein fibres
Wool and silk have a natural affinity for tannins and can take Acacia Extract readily.
Begin at the lower end of the suggested quantity range. Strong tannin concentrations may make protein fibres feel firmer or more astringent.
Avoid excessive heat, alkalinity and prolonged iron treatments.
Colourfastness
Acacia can produce good wash and lightfastness when the fibre is correctly prepared and the extract is properly applied.
Performance depends on:
- Fibre type
- Mordanting method
- Depth of shade
- Iron concentration
- Water chemistry
- Washing and aftercare
Iron may deepen and improve the stability of some shades, but excessive iron can weaken the textile.
About Black Wattle
Black Wattle is native to southeastern Australia and is now cultivated in tropical and subtropical regions, including South and East Africa, Brazil and India.
Its bark naturally contains high levels of proanthocyanins and related flavonoids. It is one of the world’s most important commercial sources of condensed plant tannins.
Natural variation
This is a concentrated botanical extract. Colour, particle size and dye strength may vary slightly between batches.
Storage and safe handling
- Store tightly sealed in a cool, dry place.
- Protect from moisture and direct sunlight.
- Avoid creating or breathing fine powder.
- Wear a suitable dust mask when measuring larger quantities.
- Wear gloves and eye protection when preparing concentrated baths.
- Tannins may stain skin, equipment and surfaces.
- Follow the safety instructions for every mordant and modifier used.
- Use dedicated dyeing equipment - never food-preparation utensils.
- For textile dyeing, printing and craft use only.
- Not intended for food, cosmetic or medicinal use.
- Keep away from food and out of reach of children and pets.
What you receive
Your chosen net weight of powdered Acacia Extract, supplied in a sealed pouch.
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