Sodium Acetate - used in the Mordanting Recipe for Cotton and Linen without Tannin

🧪 SODIUM ACETATE
For Preparing Controlled Ferrous Acetate and Aluminium Acetate Solutions

Sodium acetate, also abbreviated NaOAc, is the sodium salt of acetic acid. In natural dyeing, it is used as an auxiliary for preparing acetate-based iron and aluminium treatments.

At AppleOak FibreWorks, we combine it with ferrous sulphate to create a controlled ferrous acetate solution. This provides a measurable alternative to traditional homemade iron water and is generally gentler on textile fibres than ferrous sulphate used alone.

Sodium acetate can also be combined with potassium alum to prepare an alternative aluminium acetate solution. It is not a direct replacement for the vinegar used in our concentrated, tannin-free cellulose method.

🌿 AT A GLANCE

• Product: Sodium acetate
• Formula: CH₃COONa
• Form: White crystalline powder
• Function: Mordanting and colour-modifying auxiliary
• Principal use: Preparing controlled ferrous acetate
• Additional use: Preparing aluminium acetate with potassium alum
• Fibres: Wool, silk, cotton, linen, hemp and other textile fibres
• Solubility: Water-soluble
• Application: Dissolve in warm water

⚙️ PREPARING FERROUS ACETATE

Our studio method uses:

1 part ferrous sulphate
1 part sodium acetate
1. Weigh equal quantities of ferrous sulphate and sodium acetate.
2. Dissolve both ingredients thoroughly in warm water.
3. Use the freshly prepared solution directly in the warm dye bath.
4. Begin with 1% ferrous sulphate WOF, calculated from the dry weight of the fibre.
5. Immerse for up to 10 minutes, using less time for delicate fibres such as silk.
6. Remove and hang the fibre to aerate for approximately 10 minutes.
7. Repeat the immersion and aeration cycle up to three times if required.
8. If the result remains too light, add another 1% ferrous sulphate with an equal weight of sodium acetate.

For 100g of dry fibre, begin with:

• 1g ferrous sulphate
• 1g sodium acetate

Calculate the iron percentage from the ferrous sulphate—not the combined weight of both powders.

In our experience, ferrous acetate can act more strongly than ferrous sulphate alone. Begin at 1% and remain within 1–3% WOF iron for most work.

Prepare only what you need and use the solution promptly.

🧺 PREPARING ALUMINIUM ACETATE

Sodium acetate can also be combined with potassium alum to prepare an alternative aluminium acetate solution.

A commonly used preparation combines approximately equal weights of potassium alum and sodium acetate dissolved in warm water.

This is a separate aluminium mordanting method. It is not a direct replacement for vinegar in our concentrated, tannin-free method.

Our concentrated method relies on vinegar to create a strongly acidic treatment. The fabric is then dried fully and treated with chalk. Replacing the vinegar measure-for-measure with sodium acetate would change the recipe’s acidity and behaviour.

💡 GOOD TO KNOW

• Sodium acetate is not a dye or standalone mordant.
• Use equal weights of ferrous sulphate and sodium acetate for our ferrous acetate method.
• Calculate iron percentages from the ferrous sulphate weight.
• Warm water helps the materials dissolve.
• Prepare ferrous acetate freshly and use it promptly.
• Sodium acetate and vinegar cannot be exchanged measure-for-measure.
• Follow one complete mordanting method rather than combining different recipes.

⚠️ STORAGE & SAFE HANDLING

• Store sealed in a cool, dry place.
• Avoid creating or breathing dust.
• Avoid contact with the eyes.
• Wear gloves and eye protection when preparing concentrated solutions.
• Follow the safety guidance for ferrous sulphate, alum and all other materials used.
• For textile dyeing and craft use only.
• Not intended for food, cosmetic or medicinal use.
• Use dedicated dyeing equipment.
• Keep away from food and out of reach of children and pets.
• Do not release concentrated iron or mordant solutions into drains or natural waterways.

📦 WHAT YOU RECEIVE

Your chosen net weight of sodium acetate powder, supplied in a sealed pouch.

Ferrous sulphate, potassium alum, vinegar, chalk, dyes and fibres are sold separately.

🤝 LEARN WITH US

Join The Natural Dyers & Growers Academy to share results and explore natural colour alongside fellow dyers and growers:

https://the-natural-dyers-academy.mn.co/

Product safety:

Product: Sodium Acetate
Intended use: Textile mordanting, natural dyeing and craft use only

Safety information: Avoid creating or breathing dust. Avoid contact with the eyes. Wear suitable gloves and eye protection when preparing concentrated solutions. Follow the safety instructions for all mordants and iron salts used with this product. Not intended for food, cosmetic or medicinal use. Keep away from food and out of reach of children and pets.