ALUM MORDANT (Potassium Aluminum Sulphate Dodecahydrate)
~ Necessary for most plant dyes to ensure colour fastness ~

Alum is considered the safest and least harmful mordant used in natural dyeing. It helps fix dyes to fibres and enhances colour retention. What many don't realise is that Alum occurs naturally in nature, and some plants, such as Lycopodium, contain natural Alum.

Mordanting Cellulose Fibres

For mordanting cellulose fibres, please refer to our blog for detailed recipes:

• How to Mordant Linen and Cotton Fabrics Successfully – AppleOak FibreWorks

• How to Mordant Linen and Cotton Successfully Without Tannins – AppleOak FibreWorks

Basic Recipe for Wool

Ingredients:

• 10%-20% Alum (based on the Dry Weight of Fibre - D.W.F.)

• Wool (or other protein fibres)

• Water

• Optional: 5% Cream of Tartar (for hot mordanting)

Instructions:

Cold Mordanting:

1. Weigh your dry textile material.

2. Soak the dry material in water.

3. Dissolve Alum in hot water and add to a mordanting pot filled with water.

4. Add pre-soaked wool and let sit for 24-72 hours.

Hot Mordanting:

1. Dissolve Alum in hot water and add to a mordanting pot filled with water.

2. Add 5% Cream of Tartar to slow down the mordant uptake.

3. Add wool and bring to 80°C for 1 hour.

4. Let cool, then rinse and dye or dry for later use.

Alum is ideal for protein fibres like wool and silk, ensuring vibrant and lasting colour results.

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POTASH – pH ADJUSTER & SCOURING AGENT

Chemical name: Potassium Carbonate (K₂CO₃) | Grade: Textile | Use rate: 3–10%

No natural-dye studio is complete without potash (Pottasche in German). This alkaline powder (K₂CO₃) is slightly stronger than soda ash and is traditionally used to raise the pH of dye baths and indigo vats, scour cellulose fibres, and intensify plant yellows such as weld by increasing alkalinity.

💡 Note: This product was previously listed as Soda Ash (Sodium Carbonate). We have updated the listing to Potash (Potassium Carbonate) to reflect the correct material.

Uses

• Boost pH in indigo, woad, or fructose vats
• Add to your scouring bath
• Intensify weld yellow and other plant yellows
• Balance acidic dye baths when needed

In a nutshell

• Material: Potash (Potassium Carbonate K₂CO₃)
• Function: pH enhancer & cellulose scour
• Dose: 30–100 g · L⁻¹ (3–10% owf) dissolved in hot water or dye liquor
• Compatibility: All natural dyes; indigo & woad vats
• Packaging: Resealable moisture-proof pouch
• Safety: Wear gloves & mask; store cool, dry, and away from acids

Basic directions

Dissolve the required potash in hot water (or directly into a hot dye bath) at 3–10%. Stir until clear, then add to the dye pot or fibre scour. For indigo vats, add potash after the pigment to adjust alkalinity before introducing a reducer.

Safety & storage

Potash is strongly alkaline. Avoid inhaling dust and protect eyes and skin. Store sealed and dry; keep away from children and acids. Dispose of effluent according to local regulations.

💡 Tip: Pair potash with our Natural Indigo Powder or Indigo Kits for a complete dye setup.

Potash vs Soda Ash Table

IRON MORDANT ~ Mordant, Colour Changer, increased light fastness

Iron (Ferrous Sulfate) is used alone as a mordant, influencing Colours and to increase light fastness when used in combination with other natural dyes.

Iron is best known for shifting yellows into greens, keep in mind that this is not given and doesn't work with every yellow plant dye, in which case it will be more of a brown. it is used to increase light fastness for weaker plant dyes, bu it will always sadden and/or darken the colours. 

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Basic recipe:

When adding Iron to your dye bath start of with 3% and use it at the end of your dye bath or as an after bath. Allow to oxidize for 10 min for full colour development.

*If you like your colours darker, increase the Iron amount by 1-2% at a time. 

**Leave for 10min than remove from dye bath - Iron will make wool brittle.

HYDROS – REDUCING AGENT FOR INDIGO / WOAD VATS
Chemical name: Sodium Dithionite (Thiox) | Grade: Textile | Use rate: ≤ 25 g per 10 L vat

Hydros—also known as sodium dithionite, thiox, or hydrosulfite sodium—is the fast, reliable oxygen remover used to bring indigo or woad vats into reduction. A quick sprinkle over the surface turns the liquor a yellow-green and readies it for dipping within about an hour. However, for best performance leave the vat for 2 days before dyeing.

Why choose our Hydros
• Consistent, high-purity powder for rapid vat activation
• Cost-effective alternative to spectralite (use a little more, save a lot)
• Fine, free-flowing granules supplied in a resealable pouch

Directions (10 L vat)

1. Set vat at 40 °C with indigo/woad and alkali already dissolved.

2. Sprinkle 25 g Hydros evenly over the surface. Always add Hydros to water—never water to Hydros.

3. Cover and wait ± 60 min. Vat should shift to yellow-green with a metallic film.

4. Stir gently, keeping air out, then begin dipping.

In a nutshell
• Function: Oxygen remover / vat reducer
• Other names: Sodium dithionite, thiourea dioxide, thiox, hydrosulfite sodium
• Compatibility: Indigo, woad, other vat dyes
• Typical dose: 2–5 g · L⁻¹ (max. 50g per 10 L)
• Packaging: Resealable moisture-proof pouch
• Safety: Wear gloves & mask; store cool & dry away from acids and oxidisers

Safety & storage
Keep sealed, cool and dry. Avoid inhalation of dust. Add powder to water—never the reverse—to prevent rapid exothermic reaction. Dispose of spent vats according to local regulations and keep away from children.

Need a full setup? Pair with our Natural Indigo Kit for a ready-to-dye bundle.

It is possible to create a vat from indigo, lime (calcium hydroxide) and over-ripe fruit such as bananas or dates that relies on the chemistry of the sugars* rather than fermentation of the fruit. But it’s easier to simply use fructose shared in

Michel Garcia’s 1-2-3 recipe. It’s very simple: One Part indigo, two parts lime and three parts fructose, plus warmth.

*Fructose and glucose found in ripe fruit are reducing sugars; ordinary sugar – sucrose – is not a reducing sugar. 

Calcium Carbonate – Chalk for Dunging & Textile Work

We are pleased to offer two high-quality sources of calcium carbonate, both perfect for dunging printed, dyed, or mordanted fibres:

1. Chalk from Blanc de Meudon (France) – A traditional, fine-textured chalk often used in textile work.

2. Local Limestone Chalk (Co. Clare, Ireland) – Sourced from our nearby quarry in the Burren, an iconic Irish limestone landscape just a short drive from our studio.

Our local limestone is rich in calcium carbonate and performs beautifully for dunging. As we collect it in its natural state, you may notice tiny stones or mineral impurities. If desired, simply sieve the chalk before use.

⚠ Please note: This product is not fit for consumption. Also, all our products are packed in resealable paper bags.

How It Works

Calcium carbonate is a key ingredient in traditional fabric treatment. It acts as a substitute for cow dung, which was historically used in the “dunging” process. By using chalk, you achieve the same result in a clean and environmentally friendly way.

✨ Suggested Use:

• Add 1–2 tsp, or approx. 1% of the dry fabric weight, to water or 1-3g/L

• Stir well to create a dunging solution

• Use to treat fabrics after dyeing or printing

Both options work equally well, allowing you to choose between the historic Blanc de Meudon chalk or our beautiful locally sourced limestone from the Burren.

GUAR GUM ORGANIC
Use: Printing with Natural Dyes | Botanical Name: Cyamopsis tetragonoloba | Alternative to: Gum Arabic | Alternative Name: Guaran

Guar Gum is derived from organic guar beans and is an essential ingredient in natural dye printmaking. It is used to create a paste that works effectively with mordant dyes , allowing for precise application. Guar Gum thickens as it absorbs liquid, making it ideal for printmaking on textiles. Use a handheld blender or mixer to ensure even dissolution, and adjust the amount as needed for the desired consistency.

Key Features:

• 100% Organic Guar Gum
• Alternative to Gum Arabic
• Used for printing with mordant dyes & Indigo
• Thickens naturally for better application
• Helps create a mordant carrier for cellulose fabrics
• Best mixed with a handheld blender for smooth consistency

Function:
Guar Gum acts as a mordant carrier in natural dyeing. When combined with mordant-based dyes, it forms a rubber-like substance that can be drawn or printed onto fabric. Once dried, the gum must be removed with a Chalk and Wheat Bran solution, followed by a rinse. The fabric is then ready for dyeing. After dyeing, rinse thoroughly and boil with a small amount of organic washing-up liquid.

Basic Recipe for Guar Gum Mordant Carrier (for Cellulose Fabrics):

Ingredients for 100g:

• 10g Alum
• 5g Soda Ash
• 84g Vinegar (5% Acetic Acid)
• 1g Guar Gum

Storage & Usage:

• Once mixed, the solution will only last a couple of days.
• Store in the fridge and use fresh for best results.

Enhance your textile printing with this essential natural thickener, perfect for artists and dyeing enthusiasts.

Sodium Acetate ~ Used to turn Ferrous Sulfate into Ferrous Acetate; used in the Mordanting Recipe for Cotton and Linen without Tannin (see below)

Sodium acetate, NaCH₃COO, also abbreviated NaOAc, is the sodium salt of acetic acid. We use Sodium Acetate to turn Iron into an easier digestible version of itself, Iron acetate. Similar to 'Iron Water' but you can control the amounts. Iron acetate is not as harsh on the fibres and can be easier digested by nature or your septic tank when turned into rust. Once made, it has no shelf life and needs to be used immediately. 

For mordanting Cellulose fibres, please choose one of the following recipes on our blog:

How to mordant linen and cotton fabrics successfully – AppleOak FibreWorks

How to mordant Linen and Cotton successfully without Tannins – AppleOak FibreWorks

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Basic recipe: 

1part Ferrous Sulfate

1part Sodium Acetate

Mix and dissolve in Water. I find that it makes the iron stronger and we only use 1% of Iron acetate on most recipes. Warm water will also intensify the reaction.

CREAM OF TARTAR ~ To change colour (PH indicator) and soften fibre

Cream of Tartar, also known as potassium bitartrate, is produced by fermenting grape juice. It is used to acidify the dye bath to effect a colour change, and in mordanting to soften wool fibers as well as slowing down the mordant uptake in a hot mordant bath.

Instructions:

In general Cream of tartar can be dissolved in the dye bath. It helps to lower the PH of the bath.
PH of Cream of tartar is 5.

SODA ASH – pH ADJUSTER & SCOURING AGENT

Chemical name: Sodium Carbonate (Na₂CO₃) | Grade: Textile | Use rate: 3–10%

No natural-dye studio is complete without soda ash (Soda in German). This alkaline powder (Na₂CO₃) raises the pH of dye baths and indigo vats, scours cellulose fibres such as cotton and linen, and brightens plant yellows like weld by increasing alkalinity.

💡 Note: Soda ash is milder than Potash (Potassium Carbonate), making it suitable for situations where a gentler pH adjustment is preferred. If you bought our 'Soda Ash' in the past, you would be looking for Potash, rather than this new Soda Ash listing.

Uses

• Boost pH in indigo, woad, or fructose vats
• Scour cotton, linen, hemp, and bamboo before mordanting
• Intensify weld yellow and other plant yellows
• Balance acidic dye baths when needed

In a nutshell

• Material: Sodium carbonate (soda ash, Na₂CO₃)
• Function: pH enhancer & cellulose scour
• Dose: 30–100 g · L⁻¹ (3–10% owf) dissolved in hot water or dye liquor
• Compatibility: All natural dyes; indigo & woad vats
• Packaging: Resealable moisture-proof pouch
• Safety: Wear gloves & mask; store cool, dry, and away from acids

Basic directions

Dissolve the required soda ash in hot water (or directly into a hot dye bath) at 3–10%. Stir until clear, then add to the dye pot or fibre scour. For indigo vats, add soda ash after the pigment to adjust alkalinity before introducing a reducer.

Safety & storage

Soda ash is strongly alkaline. Avoid inhaling dust and protect eyes and skin. Store sealed and dry; keep away from children and acids. Dispose of effluent according to local regulations.

💡 Tip: If you need a stronger pH adjuster, try our Potash (Potassium Carbonate K₂CO₃).

Potash vs Soda Ash Table