Our Dyeing Philosophy
Thoughtful choices, continuous learning and a deep respect for natural colour.
At AppleOak FibreWorks, we have worked with natural dyes for over twenty years. During that time, our approach has constantly evolved, shaped by practical experience, research, experimentation and a growing understanding of the environmental impact of textile dyeing.
We believe that natural dyeing can be a more sustainable way of working with colour, but not simply because the dyes come from nature. How we grow and source our dyes, which mordants we choose, how much water and energy we use, and what happens to our waste all matter.
Our aim has always been to produce beautiful, lasting colours while reducing our environmental impact wherever possible.
And we are still learning.
Choosing Our Mordants Carefully
Mordants are an essential part of achieving lasting colour with many natural dyes, but not all mordants are equal in their environmental impact or their effect on fibres.
We have consciously chosen to avoid mordants based on chromium, tin and copper, despite their ability to produce certain colours and improve some dyeing results.
Instead, we work with a carefully selected range of mordants and modifiers, choosing each according to the fibre, the dye and the desired result.
Our Mordants & Why We Use Them
| Material | How and why we use it |
|---|---|
| Potassium Aluminium Sulfate Dodecahydrate (Alum) | Our principal mordant for protein fibres such as wool and silk. We favour cold-water mordanting, allowing additional time rather than using heat. This reduces energy consumption while preparing the fibres for dyeing. |
| Ferrous Acetate | We prepare our own iron acetate treatment by combining ferrous sulfate and sodium acetate. We use it selectively to deepen and modify colours, favouring this approach for its gentler performance on textiles and nature in general. |
| Plant-Based Tannins | An essential part of our traditional two-step mordanting process for cellulose fibres such as cotton and linen. Tannins prepare the fibre for the subsequent aluminium treatment and can also influence the final colour. |
| Alum & Soda Ash | Following the tannin treatment, we use a carefully prepared combination of potassium alum and soda ash as part of our cellulose mordanting process. |
| Aluminium Acetate | Another option for the aluminium stage of cellulose mordanting, generally used in combination with an appropriate tannin pretreatment. |
| Our Own Aluminium Acetate Concentrate | For projects requiring a clean white background, where tannins may affect the colour of the fibre, we prepare our own concentrated aluminium-based treatment using potassium alum and vinegar. This is a separate preparation with its own method and application requirements, rather than a direct substitute for our standard tannin-based process. |
A Little More About Our Approach
Cold Mordanting — Time Instead of Heat
For wool and silk, we use potassium alum in cold-water mordant baths, giving the process more time - 24h to up to two weeks - rather than heating large quantities of water.
This has been part of our professional dyeing practice for many years. By avoiding unnecessary heating during mordanting, we reduce energy consumption while treating the fibres gently.
Cellulose Fibres — Building the Mordant in Stages
Cotton, linen and other cellulose fibres require a different approach from wool and silk.
We favour a traditional two-step mordanting method, beginning with tannins and following with an aluminium treatment.
Our usual process combines tannin preparation with a subsequent alum-and-soda-ash treatment. Aluminium acetate can also be used in an appropriate mordanting sequence.
In our practice, aluminium acetate alone does not replace the full tannin-and-aluminium process when we want the results of our established two-step method.
For work where a white background must be preserved, we have developed a separate concentrated aluminium treatment, prepared using potassium alum and vinegar, which allows us to explore mordanting without introducing the colour that certain tannins can impart.
Iron — Carefully Selected and Sparingly Used
Iron is a useful colour modifier, particularly for deepening shades and producing olive greens, greys and darker colours.
Rather than applying ferrous sulfate directly, we prepare our own ferrous acetate using ferrous sulfate and sodium acetate.
We favour this preparation because of its behaviour in our dyeing processes and its less aggressive effect on textiles when appropriately formulated and used.
However, iron remains a substance that requires care. Excessive concentrations can damage fibres, and its environmental behaviour depends on the chemistry of the solution and how wastewater is managed.
Our guiding principle is simple: use the appropriate mordant, use only what is necessary, and continue investigating better alternatives.
We also reuse suitable mordant baths wherever practical, making the most of the materials already in use.
None of these substances is entirely without environmental impact. Alum requires industrial processing, and metal-containing treatments must be handled and disposed of responsibly.
We actively follow developments in mordant chemistry and alternative fibre treatments, testing promising methods against the practical requirements of colour quality, durability, fibre integrity and environmental responsibility.
Working with Time Rather Than Heat
Much of our approach to dyeing has developed around the idea that higher temperatures and faster processes are not always necessary.
Over the years, we have used cold mordanting, extended soaking, carefully controlled extraction temperatures and successive dye baths to reduce unnecessary energy use while achieving good colour results.
We work to exhaust dye baths wherever practical, often producing several shades from the same dye material before the remaining colour is too weak to be useful - or drying the used material, like cochineal for example, to use again.
This requires patience and planning, but it also encourages a more thoughtful use of resources.
Other Materials We Work With
Beyond mordants, several other materials play important roles in extraction, fermentation and colour development.
| Material | Purpose |
|---|---|
| Homemade Lye / Ash Water | We prepare alkaline ash water for use in our fermentation vats, drawing on traditional methods of creating the conditions needed for indigo reduction. |
| Lime / Lime Water | Used where appropriate to establish or adjust alkaline conditions, particularly in indigo processing and dyeing. |
| Soda Ash | Sodium carbonate is used to raise pH, particularly in indigo vats and selected mordanting processes. |
| Citric Acid | Used to lower pH and adjust the acidity of dye baths or other processing solutions. |
| Tartaric Acid | Used in selected dye extraction and colour-development processes where controlled acidity is useful. |
We choose these materials according to the chemistry of the process rather than following one universal recipe.
Some are prepared in-house, others are purchased, but all are measured and used with care.
The aim is not to eliminate chemistry from natural dyeing — that would be impossible — but to understand it well enough to make more responsible choices.
Our work with indigo and woad takes this philosophy further.
Indigo, Woad and the Power of Fermentation
Indigo has become an increasingly important part of our research and production.
We are particularly interested in fermentation vats, where biological processes help create the conditions necessary for dyeing rather than relying exclusively on conventional chemical reducing agents.
Our fermentation systems make use of traditional alkaline preparations, including our own ash water, alongside careful management of temperature, pH and the biological activity within the vat.
Our vats are being established within polytunnels, where we can take advantage of the naturally warmer environment and support the process with additional temperature control when necessary.
Alongside this, we have spent years researching and developing a reliable cold-water method for extracting pigment from woad.
Reducing the need to heat large volumes of extraction water has significant potential for making woad pigment production less energy-intensive.
Our new garden studio will bring these activities together, with dedicated areas for fermentation and pigment extraction close to the plants themselves.
Harvesting, processing and experimentation will all take place within the same growing environment.
Water from these processes is intended to pass through a dedicated treatment system before being returned to the garden for irrigation, where appropriate.
We see this as an opportunity to develop a more connected approach to natural colour production, one in which growing, extraction, dyeing and water management are considered together.
Research, Collaboration and Continuous Learning
After more than twenty years of dyeing, we still find ourselves questioning established methods and discovering new possibilities.
That curiosity is an essential part of how we work.
Our involvement with European Fibreshed, where Jennifer and others contribute specialist knowledge and advice on natural dyeing, keeps us connected to wider conversations about responsible textile production, regional supply chains and better ways of working with natural materials.
We value the exchange of knowledge between dyers, growers, researchers and textile professionals, and believe that collaboration is essential if natural dyeing is to continue developing as a practical and environmentally responsible process.
Sharing knowledge is just as important to us as developing it.
This philosophy is at the heart of our Natural Dyers & Growers Academy, where we bring together practical experience, ongoing research and a worldwide community of dyers and growers. Through courses, workshops, collaborative projects and conversations, we encourage curiosity, experimentation and a deeper understanding of natural colour.
Our One-Year Professional Natural Dyeing Course grew from this same commitment. Developed from decades of hands-on production experience, it provides a comprehensive foundation in natural dyeing, from fibres and mordanting to colour development, professional practice and sustainability. Just as importantly, teaching encourages us to continually revisit our own methods, question assumptions and explore new approaches.
We regularly trial new materials and techniques, revisit processes we have used for years and share our findings through the Academy.
Learning, research and teaching are not separate parts of our work. They continually inform one another.
A process that worked well ten years ago may not necessarily be the best approach today. And that is precisely what keeps our work so interesting.
Why We Work This Way
We don't believe that calling something natural automatically makes it sustainable.
Natural dyeing still requires resources, and there are environmental consequences to every choice we make.
What we can do is take responsibility for those choices.
For us, that means selecting our mordants carefully, reducing unnecessary heat, using dyes and water thoughtfully, growing more of our own colour, investigating biological processes and continuing to improve our methods as new knowledge becomes available.
Bringing our dyeing, research and pigment production closer to our garden is another step in that direction.
We don't claim to have found the perfect way to dye.
But we are committed to continually finding better ways.
And after twenty years, that commitment is stronger than ever.
