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Natural Dyes for Wool: Cutch

By Hannah Thiessen on April 14, 2021

natural acid dye


Continuing with our loose theme of exploring the world’s fascinating, dyeable materials from trees and branches, in this blog we’ll be applying Cutch, a dye that comes from the heartwood of the acacia catechu tree. This tree grows in India, Burma, Indonesia and Peru, and my cutch dye comes from the Indian variety and is able to achieve a range of soft, golden-brown tones into medium cinnamon tones.


While generally it’s better to use this warm hue in a high weight-of-fiber ratio (20-50% is recommended from my source for this dye, Maiwa), I have gotten some unusually pretty golden tones when going a bit light on the ratio as well. Being that we’re transitioning into a sunny, golden spring where I live, I felt that a neutral with a bit of shimmer and drape would feel light and lovely! 


I chose Knomad’s Latte yarn, which is made from 100% Baby Alpaca, sourced and milled in Peru. Baby alpaca is an ultra soft fiber and Knomad’s undyed version is even more so, with a really fantastic shine to it, too. I knew it would be perfect for this golden hue, so I grabbed two skeins and went to work! 


natural acid dye


How to Naturally Dye Wool with Cutch


For this dye experiment, you’ll want the following materials on hand. Remember, anything you use for natural dyeing must not be used again for food or food prep at any time, and you’ll want to store it separately to avoid any cross-contamination. 


  • 1 large stainless steel or aluminum soup pot or stock pot

This should be big enough to hold 1-2, 100 g skeins of yarn, covered in water and fully submerged with room to move around.


  • Dedicated tools: measuring cup, spoon for stirring, measuring spoons


  • A heat source

This could be your at-home stove with good ventilation, a hot plate, a propane burner or even a crock pot. If you’d like to use an upcycled crock pot, you will not need the stock pot, but it will need to stay fully dedicated to natural dyeing as dyes are not food safe.


  • A water source

Natural dyes do use a lot of water–for prepping your fibers, creating dye baths, and rinsing finished yarns. You can use rainwater if you like, especially if you find your tap water is influencing your colors negatively. You can test your water’s pH with strips and see how ‘neutral’ it is if you like. 


  • A respirator or face mask

I typically would not use a respirator or face mask when moving around larger dye goods like flowers or leaves, but if you are using anything powdered–the chemicals we use to mordant, or any powdered dyes–I recommend having one on. These ultra-small particles just aren’t good to breathe in! 


  • A scale that can measure grams in small quantities

If you already have a baking scale, you can use it here, just make sure not to let any dyes or materials touch the scale directly. Simply use the tare function to zero-out the weight of any vessels you’re using to measure, then clean off your scale thoroughly after use. 


  • Aluminium sulfate or Aluminium Potassium Sulfate*

Mordants are chemicals that bind to both the fiber and color, acting as a bridge to attach color molecules to your wool. This chemical is the safest of a handful of options and is popular with many natural dyers. It will only bind color to protein fibers, not cellulose ones–so color taken by the wool may not be taken up the same way by any blended fibers (like cotton, hemp, linen or nylon). 


  • Cream of Tartar*

Cream of Tartar adds a little softness back into your bath and prevents your wool from feeling too crunchy at the end of the dyeing process. 


  • Cutch powder

I’ve used a pre-prepared, ultra-fine powder for this experiment. Depending on the year, the age, quantity and source of your powders, some colors may appear differently. 


  • 2 skeins of Knomad Latte

For this dye experiment, I selected Knomad Latte, a decadent 100% Baby Alpaca yarn with 291 yards per 100g hank. I chose this base for the drape and how beautifully alpaca takes even soft colors–the halo somehow enhances the overall look.


  • Old clothes

Cutch dust has a way of making it onto whatever you’re wearing and making it look dirty. Wear something you don’t love when working with any natural dyes. 


  • Gloves

Rubber gloves or kitchen gloves, which can be re-used multiple times, are my preference here. While most natural dyes are perfectly safe to handle with your hands, you’ll be washing, rinsing, and in and out of water a lot, which can damage your nails and cuticles. Keep those knitting hands pretty and get some gloves. 


*These items have been pre-calculated in the amount you need for this project, dyeing 200 g of wool, however, you can also do your own calculations using the mordanting guide below. 


natural acid dye


Step 1: Prep your fiber. Knomad pre-scours and washes their yarns before shipping them to us, so there should be no need to heavily clean the fibers–simply remove the tags, leaving all the ties, and open the hank into a big loop. Add reinforcement ties if you feel they’re necessary, and soak the fiber in warm water for an hour to get it fully saturated (typically 1 hour). Alpaca can be slinky, so make sure none of your ties are too loose or risk snapping a strand when you’re too rough getting it out of the bath (ask me how I know). 


Step 2: Measure the alum. Wearing a respirator or face mask, measure out 12% of your weight of fiber (WOF) in alum sulfate. Here’s the math for our experiment: 


200 x 0.12 = 24 g of aluminum sulfate

Hot tip: weigh out how much alum is in a tablespoon (dedicated tablespoon) and then calculate moving forward about how many tablespoons you’ll need to simplify future measuring. 


Step 3: Add hot water to your alum in a small mixing container. I like to use empty, recycle-ready plastic containers. Stir the alum and water mixture until the alum is fully dissolved and the water looks cloudy or clear, but has no visible grains in the bottom of the container. Measure out 1 tbsp of Cream of Tartar and dissolve it into the water while it’s still warm. 


Step 4: Transfer your mordanting solution to a larger stock pot, and fill with enough water to cover your skeins of yarn (don’t add them until the pot has all the water in it). Stir and then add your yarn, moving it around to let it fully absorb the mordanting solution. Set on low heat and simmer (do not boil) for 1 hour. Allow to cool overnight with the yarn in the solution. 


Step 5: Prepare your dye good solution. 

Measure out 1 tsp of your dye powder per 100 g of fiber and see how you like the results. Often, these powdered dyes are a bit more potent, and require less dye to fiber in the ratio. Powders should be prepared with smaller quantities of water and left overnight to more thoroughly mix, or these dyes have a tendency to separate and make one part of your project darker than the other (or have little speckles, which can be cool, if that’s what you wanted). I mix powdered dyes up in a bottle with a well-sealing lid, fill the bottle halfway with water and shake a few times over the course of the day. Leave it overnight in the bottle. 


Step 6: Prepare the yarn. Drain the water from your yarn soak, and push a little of the extra retained water out with your fingers. Not too much–liquid being held by the fiber will help draw the dye into the yarn, so we don’t want to take it all out and risk too much splotchiness in the final fiber.


natural acid dye


Step 7: Prepare the dye bath ahead to allow the cutch enough time to dissolve. The cutch I use dissolves quite well in hot water, especially compared to many other wood-based dyes that can benefit from an overnight soak. To get a very soft, golden tone, I used only 2 tbsp of cutch for 200g, but if you’d like a richer, more cinnamon color, you can experiment with closer to 50% weight of fiber (so 100 g of powder to 200 g of fiber). 


Step 8: Add your yarns gently to the dye bath, making sure that yarn has enough room to move around but is mostly submerged in the pot. If you need more water, it’s okay to add some here.


Place your pot on the heat source of your choice and increase the temperature gradually to a heat just under simmering. If you have a thermometer, you’re going to first lift the temperature to 90 F (32 C), stir, and then lift the temperature again to 180 F (82 C). I don’t have a thermometer, so I just eyeball it, and that’s okay too. You want the water hot enough for steam to be rising off it, but not so hot that it’s bubbling, boiling, or moving your yarn around for you. Keep the dye bath at this temperature for an hour, stirring occasionally to move the fibers around and keep them from collecting dye only on one side. After an hour, turn the heat off and let it cool. 


Step 9: Lift a bit of your yarn from the pot with a spoon and evaluate the color–remember, it will typically be 1-2 shades lighter than what you see on the wet fiber. If you like the color as-is, remove the yarn from the pot and move to the next step. If you would like to see the color deepen or strengthen a bit, leave it in the pot overnight, stirring one more time before you go to bed. 


Step 10: Remove your yarns from the dye bath and smoosh out some of the extra dye–set the wool aside. Fill a sink, basin or bucket with room temperature water and add your yarn, moving it around with your hands to allow dye release. When the water is dark, drain it and do this step again. Rinse until the water is mostly clear to ensure that no dye particles will transfer to hands or clothing while working with the finished yarns. If you want, you can add a little bit of wool wash to one of these rinse baths to improve the softness and scent of your finished yarn. 


Step 8: Hang your hanks of yarn to dry out of the direct sun (I like to use a portable hanging rack). They will drip a little bit, so if you need to dry them indoors, I suggest putting them in a bathtub or in a room with a drain (like a basement). Depending on your humidity and weather, it can take 1-2 days for yarn to fully dry, but maneuvering it so that the same part of the hank is not always hanging down can help move this process along a bit. 


natural acid dye

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Hannah Thiessen

Hannah Thiessen is a passionate, self-proclaimed “wool obsessive”, who has worked in the yarn manufacturing, design, and production sector for the past decade. Through her books Slow Knitting (Abrams 2017) and Seasonal Slow Knitting (Abrams 2020), Hannah explores the relationship between the crafter and end project and seeks to provide a deeper, more holistic practice for fiber aficionados at all levels. On the Knomad blog, Hannah will be exploring natural dyeing on Knomad’s non-superwash bases, providing insight on the many natural dye products, extracts, and botanicals available to us, and expanding on the potential palette of color that surrounds us daily.

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