Today I want to share a simplified mordanting method with you: using the cold water mordant aluminium triformate. Aluminium triformate has numerous benefits compared to other mordants which we will explore in detail in this post.
Table of Content:
- What is aluminium triformate?
- What is mordanting?
- Benefits of using aluminium triformate as a mordant
- How to mordant with Aluminium Triformate: Step-by-step Tutorial
- Color Comparison: Aluminium Triformate vs. Alum
If you want to learn more about how to mordant a skein of yarn using aluminium triformate, you can check out this video on my Youtube channel:

What is aluminium triformate?
Aluminium triformate (also known as aluminium formate) is the aluminium salt of formic acid. It comes in the form of a white powder. It is commonly used to clean wastewater, tanning leather, and preparing paper [1]. When it comes to natural dyeing, aluminium triformate can be used as a mordant.

What is mordanting?
If you have never dyed a skein of yarn or a piece of fabric before, let’s start at the beginning. Mordants are essential if you are dyeing either protein or cellulose fibers with natural dyes. A mordant or dye fixative is a substance which is used to set dyes on fibers. It forms a coordination complex with the dye which attaches to the fiber. As a result, mordants enhance the wash- and lightfastness of the dyed yarn or fabric.
When it comes to choosing a mordant, there are several options available. They can generally be grouped into metal-salt mordants (like alum) and plant based mordants (like tannins). I have written a blog post all about different types of mordants which you can find here: What is a Mordant? (Mordants for Natural Dyes).
Benefits of using aluminium triformate as a mordant
But what makes aluminium triformate stand out among the different types of mordants you can use for natural dyeing purposes?
Reason #1: Versatility
One of its major benefits is the fact that aluminium triformate can be used for both protein (wool, silk) and cellulose (cotton, flax, hemp) fibers.
Reason #2: Energy Consumption / Ease of Use
But there is more. Another advantage of using aluminium triformate as a mordant is that no addition of heat is required, meaning the mordanting can be done at room temperature. Not only does this mean that you need less energy in the form of power consumption, it is also an easier process. You simply make the mordanting solution, immerse the fiber in it and you are done. You don’t have to check the temperature and give it a stir from time to time. After a couple of hours (or even days, depending on your schedule), you take the fiber out of the mordant bath and it is ready to use!
How to mordant with Aluminium Triformate:
Step-by-step Tutorial
1. Safety precautions
Don’t use the same pots and utensils for natural dyeing that you use for food preparation. Always wear gloves. Creating the mordant solution should be done in a well ventilated area. Do not ingest. Do not breathe dust. Wear protective gloves, safety goggles and a dust mask when handling fine dye powders and mordants.
2. Calculating
Aluminium triformate can be calculated as either grams per Liter (gpL) or weight of fiber (WOF).
Option #1: gpL method
100 g aluminium triformate can be used to mordant up to 1,5 kg of cellulose fibers (cotton, linen) or 3 kg of protein fibers (wool). You will need 5 liter of water for 100 g aluminium triformate, this creates a 2% solution.
Option #2: WOF method
The second option is to calculate the amount of aluminium triformate you need based on the amount of fiber you want to mordant. The recommended amount is 5-10% WOF. For example, if you want to mordant a 100 g skein of yarn (3.5 ounces), you will need 5-10 g of aluminium triformate.
3. Step-by-Step Tutorial
- On the first day, scour the yarn or fabric thoroughly in a bucket filled with room temperature water. Gently press the fiber under the water surface and make sure that it is fully immersed in the water bath.

- Day 2:
Option A: Gpl method:
Measure 20 g of aluminium triformate using a scale and add it into a pot filled with 1 liter of lukewarm water (122 F / 50 °C max). Stir with a metal or wooden spoon until the powder is fully dissolved.
Option B: WOF method:
To mordant a 100 g skein of yarn (3.5 ounces), measure 5 g of aluminium triformate. Add the mordant in a pot filled with lukewarm water (122 F / 50 °C max) and gently stir with a metal or wooden spoon until the powder is fully dissolved.
Take the yarn or fabric out of the water bath and gently wring it out. It should be wet but not dripping. Add the fiber to the pot containing the mordant solution and make sure that it is fully immersed in the mordant bath. Leave the fiber in the pot for at least 8 hours.
The time period can be extended without any issues. You can leave the yarn or fabric in the mordant for days, but I usually leave it just overnight.

- If you are ready to proceed with the natural dyeing process, take the fiber out of the mordant bath. Gently squeeze out the excess water, give the yarn or fabric a quick rinse and you are ready to go.
4. Reusing the mordant bath
When choosing the GpL method, you can reuse your mordant bath multiple times. In the example above we created a mordant solution that can be used for up to 300 g of cellulose fibers (cotton, linen) or 600 g of protein fibers (wool) (using 20 g of aluminium triformate and 1 liter of water).
Color Comparison: Aluminium Triformate vs. Alum
On the picture you can see two skeins of yarn (a blend of 85% wool, 15% linen) that were dyed with madder. The left skein has been mordanted with aluminium triformate and the right skein has been mordanted with alum. There is no significant difference in color intensity visible.

Want to learn exactly how to get started dyeing yarn with natural dyes?
This free guide for beginners walks you through the eight steps of dyeing a skein of yarn using natural dyes.

Pin It For Later: Cold Water Mordant: Aluminium Triformate

Further Reading:
[1] https://www.dharmatrading.com/dyes/aluminum-triformate.html
Hallo again,
I forgot my other question. So if I understand that to calculate the alum triformate using gpl method I would use 20 grams of triformate & that should be enough to mordant my 1150 grams of cotton fabric. But it sounds like if I use the wof, I would be using 57.5 grams of triformate? Am I understanding that correctly?
Again thank you,
Monica
Hi Monica,
Please excuse the belated reply, I was on vacation.
If you use the gpL method, you need 100 g of aluminium triformate and 5 liter of water for 1.5 kg of cellulose fiber (e.g. cotton fabric). So if your fabric weighs 1.15 kg, you will need 76.7 g of aluminium triformate and 3.8 L of water.
If you calculate with the WOF method, I would go with 10% WOF. So in your case, this would mean 115 g aluminium triformate (10% of 1150 g).
I hope this makes sense?
Hallo, I’ve been learning & experimenting with ecoprint bundle printing & natural dyeing. I’ve used Alum but so many steps to do. I purchased Aluminum triformate & read it’s so much easier & less steps.
I have few questions. So you don’t have to do a vinegar splash bath after scoring to use triformate? Also you don’t have to do phosphorus chelation bath with wheat bran or calcium carbonate, if I’m understanding that correctly?
Triformate sounds awesome!
Appreciate your advice,
Monica
Panama City, FL
You are right, you don’t need a vinager or phosphorus chelation bath when using aluminium triformate.
Greetings! I ran across my first of your videos on YouTube last night, and was blown away! Not only do you present well, but your content is excellent! I have been casually researching natural dyeing for about a year, and experimenting, mostly with pale success. I learned about mordanting, and what it does to attach the color to the fabric. Your video where you explained why it is really best to use aluminum triformate because it works on both protein and cellulose fibers. My heart leapt!
I have found basic ratios of the chemical to water, but need to do more research about water temperature, etc.
Aluminum triformate is apparently newer, and it is hard to find in the US. Do you know of any resources for obtaining aluminum triformate? I am not unschooled in scientific practices, like wearing a respirator, goggles, and gloves. Clothes covering me, perhaps an apron. But if I cannot obtain it, I can only collect and plan.
I will watch more of your material. It may answer the questions about process that I have, but do you know of a combination of alum with other metals that would achieve the same results across the board?
We live in a semi-arid climate, and I want to use cellulose fabrics. That does not mean that I am not scouting the thrift stores for old pale silk scarves or shirts or anything, really. An old wool blanket would be keen, but because of the outbreak of bed bugs, I’m not sure they still accept bedding.
Using repurposed materials and things I can harvest, either in my garden, kitchen, or in the wild. There is not much wild around here that is traversable or not fenced with barbed wire (cattle). I am planning a trip to a nearby wildlife refuge in a couple of weeks, and I know how to responsibly, sustainably harvest. Mostly seeds.
Your grace is a gift. Thank you.
Sincerely,
Lezlie Christian
Hi Lezlie, Thank you so much for your kind words, your comment totally made my day!
Did you know that I offer a free guide about dyeing fiber with natural dyes? You can find it here: https://adept-artisan-8032.ck.page/6de92b99bb
Regarding your question about aluminum triformate, you can get it at Botanical Colors.
Foraging for dye stuff is my favorite way of sourcing dye material. Well, besides using kitchen scraps like avocado pits, onion skins etc.
Let me know if you have any other questions.
Kind regards Annika
Dear Anikka, where in Europe we can get the aluminium triformate? Do you have a link or maybe a suggestion? Thank you in advance, Cecilia.
Hi Cecilia, You can get it here: https://shop.pflanzenfaerber.eu/beizen-und-entwickler/238-al-o-kaltbeize-aluminiumtriformiat-100g.html