Natural Dyes: Blackberry
2005 August

Blackberries: berries and brambles Dyebath: berries only Dyed yarns from berries and brambles

It is widely understood that most natural dyes are to some extent not light-fast or wash-fast. Some of the colors may fade out completely over time or from washing. Other colors may take on a brownish or greyish cast. This is okay with me. When I want color-fast, I work with chemical dyes.
The inexact approach that I take in my pursuit of natural dyes may seem somewhat incongruous to those who have watched me rip out half a garment to correct an error in my knitting, even if the error is subtle enough that only I will be likely to know it is there. I definitely have the capacity to be a perfectionist, and I do exercize that capacity in many of my pursuits. With natural dyes, however, I do not tend to weigh and measure with precision, and so this page will not contain any detailed recipies, but instead will present an overview of the basic process.
It should be noted that there are distinct advantages to taking detailed notes on the process, especially when working with hazardous substances. After all, if poison control needs to be called, it would be comforting to know that they could be accurately informed as to what substances were potentially involved!
*** Safety is extremely important! Especially if you are using your kitchen, or if you have children or pets which might get into your dyepots! Use non-toxic plants. Use alum as your mordant of choice. Use dedicated dye-pots that are never used for cooking or food storage! Clean up regularly and carefully! Use gloves to protect your hands. When working with powders, use a dust mask. Don't leave food on the counter while you're working with dyes. Don't eat or drink while you're dyeing. Keep your craft (supplies, processes) as separate as possible from your food (supplies, and processes). Even if you are using non-toxic substances, these are good habits to foster. ***

Materials Safety Data Sheets (MSDS) for Alum and Iron

Since I am not keeping detailed notes, I focus on the use of non-toxic plants for the dyestuff and alum (aluminum potassium sulfate) for the mordant. I get my alum from a dyer's supply. (A safer (but more expensive and slightly less effective) form of alum can be purchased in small quantity at the grocery store from the spice section.)

I also occasionally use very small additions of iron (ferrous sulfate). It takes surprisingly little iron to make a strong change in color. Simply using a cast-iron pot can be sufficient to affect the change of color, and too much iron can damage wool and other protein fibers.

I consider most other mordants (such as chrome and tin) too dangerous and strongly discourage using them.

When working with natural dyes, there are many factors which can influence the end result. To start with the obvious, the type of fiber matters significantly. Wool takes the color differently than cotton, sometimes so much so that it seems impossible that the two skeins could have come from the same bath! Other, less obvious factors include: the season in which the dyestuff is gathered, the health of the dyestuff, the condition of the soil the dyestuff grows in, the acidity of the dyebath, the condition of the water used (hard, soft, chlorinated, etc), the temperature of dyebath, the length of time the dyebath is held at a particular temperature, the length of time the fiber remains immersed in the dyebath, etc, etc, etc!
With so many factors that can impact the end results, I've taken a random and playful approach, experimenting to discover how wide a spectrum of results I can achieve, rather than trying to recreate certain favorites. I've been working with natural dyes in this way for about five years now and I'm starting to be able to interpret some of the results; for example, there's a very distinctive greyish cast that occurs when iron is used as one of the mordants, whether that iron is mixed into a solution from powder, or whether it is introduced through the use of a cast-iron pot.

A mordant is important for most natural dyes. A mordant is a chemical that attatches to both the fiber and the dye molecule, thus bonding the dye to the fiber. Many potential mordants (chrome, copper, and tin for example) can be downright poisonous and should be used very cautiously and with excellent ventilation. Many potential dyestuff can also be poisonous. Rhododendron leaves, for example, are poisonous. They give a tan dye, but is it worth the risk? There are many lovely colors to be discovered from non-toxic sources! Educate yourself, and do everything you can to minimize your risks.
Even if you do limit yourself to just alum as a mordant, there is still a wide spectrum of results to obtain from even just one source. Blackberries are a good example. Ripe berries have given me rich maroonish to purplish colors. When I've clipped the bunches of berries and included twigs, and leaves (and I'm sure the occasional unfortunate bug) I've ended up with a reddish-brown. If I remove all the berries, I get a yellowish-brown. You could try using just the leaves, or just the roots and would probably get a still wider pallette of colors. It's also quite possible that the leaves or brambles would give different colors depending upon the season in which they're gathered.
I treat both wool and cotton exactly the same, and have had good experiences using alum as the primary mordant for both. In previous seasons I have put the mordant into the dyebath. This season I pre-mordanted the yarns and it seems to have resulted in deeper, richer colors and a longer-lasting dyepot. Adding the mordant to the dyebath would still be useful for dyeing loose fiber for spinning as it would help minimize the risk of felting.

I dissolve approximately 1 Tablespoon alum in 1 gallon of hot water, then let it cool until it's just warm (not hot) so that I don't shock the wool too much by the sudden heat change. (If I'm impatient, I soak cotton first since it is less sensitive to high heat. When I've put dry wool into very hot water, I've ended up with scratchy wool.) I let the wool (or cotton) soak for at least half an hour to become completely saturated, then wring the skeins and set them aside, ready for the dyepot. I then soak the next batch of skeins in the leftover solution, repeating the process as many times as I can until there is no longer sufficient solution for the next skein to absorb. Since each skein of yarn pulls some of the alum out of the water, the amount of alum available to successive batches is diminished. Less alum means less ability for the dye molecules to bond to the yarn, so this is one way to get a successively paler range of color from one dyebath. (Another way would be to change the amount of time the mordanted yarn rests in the dyebath.)
I have a favorite pot for my natural dyes; it is stainless steel, has a 20 quart capacity, and has a strainer bucket which holds the yarns up off the bottom of the pan (very useful! This helps avoid scorching the fiber.) Stainless steel is relatively non-reactive, so it keeps the colors truer. Using a different type of pot (aluminum, cast iron, copper...) will give you different results, and can be a very safe way to introduce very minimal mordanting effects from these metals in a stable and non-toxic form.
I gather my dyestuff the easy way: I clip the little bunches of berries off the thorny bushes into a large plastic bucket and do the sorting at home where I can sit down and take my time. The one drawback to this method is the number of bugs that come home with me. If you gather your berries (and brambles) this way, I suggest sorting them outside so that the bugs don't end up in your house!
For a berry dyepot, I pluck the ripe berries off my little bramble-bits and toss only the berries into my stainless pot half full of water. As I've already mentioned, I don't keep very detailed notes, so I'm not really able to tell you how many berries are sufficient, but basically the more berries you put into the dyepot, the deeper the color and the more skeins the dyepot will yield. When I get too scratched up by the thorns to pluck even one more berry, (or when there's no more room in the water for even one more berry,) I put the pot on the stove on the lowest heat possible and bring it up to a low simmer. After about half an hour, I crush the berries in my dedicated craft-use blender. (I have also used a potato masher when my blender was unavailable.) I have learned to be very careful if I try to crush the berries while they are hot! If I'm using a potato masher, I transfer just the berries (none of the liquid) into a bowl to crush them. Again, the strainer basket comes in handy! I simply lift up the strainer basket to let most of the liquid drain off the berries. If I am planning to use my blender, I then pull some of the liquid out of the pot into a separate container so that I can place into the blender an equal measure of berries and of liquid puree them together. Adding the liquid to the blender with the berries helps ease the strain on the blender and helps ease the process of getting the berries back out of the blender, too. When the berries are crushed, put the resulting puree back into the dyepot with the rest of the liquid and simmer for an additional 10 - 20 minutes. The crushing step maximizes the amount of dye molecules available in the liquid. Unfortunately, it also thickens the liquid with berry pulp. The berry pulp must be strained out. Trust me, you don't want it to become embedded in your yarn or fiber.
To remove the berry pulp, I strain the liquid through successively finer-meshed sieves. When I've run out of mesh sieves, I strain the liquid one last time through a pasta strainer lined with a muslin dishcloth or old pillowcase. I find that even after all of the previous strainings, the berry pulp still clogs the muslin pretty quickly, so I keep several cloths at hand and change them as needed. Once all the liquid has been strained through the muslin, I set it aside to cool before adding the pre-mordanted yarn. Since 20 quarts of liquid can take awhile to cool, I usually let it sit overnight. In the morning I put the pre-mordanted skeins into the cool liquid, return the pot to the stove, and heat it again over the lowest heat possible until it gets to about 170 degrees or a low simmer. I then take the pot back off the stove and let the skeins rest in the liquid overnight so that the dye has the maximum chance to bond with the fiber. (If I want a paler color, I can remove the skeins after a shorter soak. Hot fiber isn't much of a joy to handle, so I have a pair of dedicated stainless steel tongs just for the task of moving the skeins around in a hot dyebath or lifting them out of one.) Letting the skeins rest overnight in the dyepot to cool makes handling them a much more pleasant process.
The next morning, I gently squeeze the excess liquid from the skeins back into the dyepot, rinse the skeins, wash them in warm water with just a little bit of a mild soap (I have been using Woolite lately), and rinse them again until the water runs clear. I then use my washing machine to spin them dry before air-drying them flat. If a washing machine is unavailable (or if the spin cycle spits water), I place the fiber or skeins in a lingerie bag tied to a string and spin it by hand. Quite a workout if I'm doing a lot of them, but surprisingly effective, especially for small batches. (The term for this method of water extraction by hand, incidentally, is "wuzzing". A fabulous word, don't you agree?)
(In some of my previous experiments, I have taken some of the skeins from the alum-mordanted overnight dye-soak and placed them (plus a small amount of the dye liquid) into a pan of a different composition (cast-iron or aluminum for example) and brought it again to a simmer, then rested it until cool before washing. I've really enjoyed the way some of these have turned out. One of my favorites is one in which only the parts of the fiber that were touching the cast iron changed color!
It is possible to create a wide range of inventive effects. By adjusting the amount of alum used you can adjust the amount of dye that bonds to the fiber. By adjusting the amount of time the fiber is immersed in the dyebath you can adjust the depth of color or potentially the hue. By suspending the skein, you can allow the dye molecules to bond to only part of the fiber, resulting in a space-dyed pattern.

There are a number of well-written books on the topic of natural dyeing, among them:
Lesch, Alma. Vegetable Dyeing. Watson Guptill Publications, New York. 1970.
McRae, Bobbi A. Colors From Nature. Storey Publishing, Vermont. 1993.
Van Stralen, Trudy. Indigo, Madder, and Marigold. Interweave Press, Colorado. 1993.
Dean, Jenny and Karen Casselman. Wild Color. Watson Guptill Publications, New York. 1999.