Natural dye tutorial: blue yarn from black beans!

It’s been a long time since I’ve been able to post, but at least I have a really awesome fiber dye experiment to share! As you can see from above, we got several lovely shades of blue —a difficult color to achieve —in a process that took about 4 days from start to finish.

A little background: now that I have a spinning wheel(!) and some wool, I’ve been wanting to learn about natural dyeing. SInce blue is my favorite color, I gravitated toward information about natural blue dyes. Turns out there aren’t that many (indigo and woad are the main ones) and they sounded like a lot of work for a first time dying project. Then I came across web posts on black beans as a blue dye. My favorites were blog posts at waysofthewhorl and brambleberriesintherain, which then led me to the discovery that there is a ravelry discussion thread (login required) that is 2 years old and 24 pages long! Needless to say, I was overwhelmed with information. At the same time, no one post seemed to describe exact amounts of beans, water and yarn used, nor exact times for the different steps involved. The credit for coming up to the solution goes to Keith (who also took the photo above): he suggested a test run of blue dyeing where we recorded the important measurements. So that is what we set out to do.

Now as a caveat: not everything went as planned, record keeping wise. Two major problems arose:

1) I was keeping some notes on Stickies on my Mac, and last week all of my Stickies disappeared from my laptop (Just one of many issues, sadly. This computer is in its death throes).

2) My camera broke during the weekend the finished blue mini skeins were drying. It took a week for me to decide on a replacement camera, another week for it to arrive from Amazon, and several more days to get a shot of the yarn in natural light. So I had to rely on my memory for the things we didn’t write down.

Nevertheless, I give you: Dyeing yarn blue with black beans: a (mostly) scientific tutorial for beginners. What you will need (amounts will be determined later):

-black beans

-water (tap is fine and what we used, but see note at the end of the post)

-non-reactive containers for soaking and dyeing (we used glass and stainless steel)

-natural fiber yarn, white or offwhite (we used Lamb’s pride, 85% wool, 15% mohair, M-10 Creme)

-Alum mordant (Aluminum Potassium Sulfate—you can find this in the spice aisle of a well stocked grocery store)

-Cream of Tartar (also in the spice aisle)

-large non-reactive pot for the stove (We used a large enamelware roasting pan. Technically this should not be a container you’re going to use for food after this, and although Alum seems to be non-toxic, I played it safe.)

-misc. items: additional yarn to tie off your skein in sections, a rack or other place to dry finished yarn


First figure out how much beans and how much water to soak them in by choosing a ratio from below.

Here are rough ratios of water to beans in each of our dye lots:

dye lot  # 1/2  = 7 to 1  (7 parts water to 1 part beans)

dye lot #1 = 3.5 to 1

dye lot # 2 = 2 to 1

dye lot #4 = 1.25 to 1

Next you should make sure that you have enough beans and water to create enough dye for your yarn. The dye lot numbers are how many cups of beans went into each. I strongly urge to get more than you think you need because beans absorb water at a higher rate than we bargained for. Originally we planned on 1 oz of yarn in each dye lot, but we had to reduce it it to 1/2 oz (.5 oz) of yarn in each.

At the start we filled each container with enough water to cover the beans plus 3 cups more. Our measurements were very odd :

#1/2 = 1/2 cup beans and 3.37 cups water;

#1= 1 c. and 3.4 c.;

#2= 2 c. and 4.125 c.;

#4=4 c. and 5 c.

And then of course, we lost some of that water when the beans absorbed it. [side note: I think the lesson is this—stick to calculating how much beans and how much water based on some sort of ratio between 7 to 1 and 1 to 1 based on the color you want, then make sure the amount of water you add is enough to cover your yarn and then some, because you will have less dye than water. Not completely scientific, but probably easier.]

We let each of these bean and water combos soak for 24 hours, stirring whenever we remembered. Then (and this is important), Keith strained out the beans, let the dye settle for an hour or two, then siphoned the water off from the top so that the bean particle matter did not make it into the final dye. From what I read, the pieces of bean tend to make the yarn more of a gray color than blue. Other people on the internet suggested spooning the water out and leaving the dregs.

When it was close to 24 hours, I started preparing the yarn. I separated it into four .5 oz skeins tied with bits of a thinner yarn to keep it from getting tangled, then unwound the skeins and soaked them in water for 1 hour.After soaking, I moved the yarn to large stovetop pot to mordant it using alum, along with some cream of tartar. Mordant is what allows the dye to adhere to the yarn and not just wash out or rub off.

I would go by Sasha Duerr’s Handbook on Natural Plant Dyes to calculate how much need: 8 percent of the fiber’s weight  for alum, 7 percent of the fiber’s weight for cream of tartar. For mordanting 2 ounces at once this comes to about 3/4 of a teaspoon each of alum and cream of tartar. I will admit that I was probably closer to 1 tsp each, because I couldn’t find my 1/2 tsp measuring spoon. It still worked.

I dissolved both into some hot water and add to the stovetop pot along with enough water to cover the fiber. Then I added the water soaked yarn and brought the pot to a simmer.**Important note: do not change the temperature of the yarn too quickly, it can cause felting** I simmered it for an hour then turned OFF the heat (I corrected this sentence—OFF, not on!). At this point you can either let it stay in the mordant pot overnight, or take it out.

I waited another 2 hours until it had cooled off, then removed the yarn and rinsed it off with clean water  that was the same temperature as the yarn to remove any excess mordant (using a little pH neutral soap is supposed to help). Finally, the fun part—adding the yarn to the dyes! As you can see, some of our dye lots barely covered the yarn, so we turned them upside down or right side up periodically to avoid unevenness in the color. We let them stay in the dye for 42 hours. I’m sure an even 48 hours would be great, but sleep comes first.

During this time, I discovered something that no other blog really mentioned: the color you see immediately can be quite different from the final color. Observe what the yarn looked like about 10 minutes after I put it in the dye: That’s right—it was a light purple color! At first I was disappointed that all our effort to get blue failed, but in an hour or two it started changing into the blue color you saw in the previous picture. I should also mention that this photo in the blue plastic jar came from round 2 of dyeing the yarn.

After I took out the four 1/2 oz. test skeins, I still wanted to dye the remainder of the creme yarn. So I soaked and mordanted the remaining 2 ounces of yarn, poured all four dye lots into the blue plastic jar, and let it stay there for 48 hours. Not very scientific, although hopefully you can see in the photos that it came out a slightly grayer and more muted shade of blue—one which I still quite enjoy.

After removing the yarn from the dye, I rinsed them with lukewarm water and hung them to dry on my laundry rack (I wish I’d taken a picture then!) Here are the differences in shades of blue when compared side by side, L to R from darkest (1.25 to 1 ratio) to lightest (7 to 1), and the extra skein made from all dye lots combined:

Even on a screen, I think the darkest one is a distinctly deeper shade of blue than the rest. The difference between the two lightest shades is less subtle here, but in person you can definitely tell. And the last one of course has a distinctly grayer tone. by the way, the undyed yarn next to that last big skein is my own handspun! I didn’t intend to include a photo of it but I’m glad Keith took it, its nice to see the blue yarn next to it.

The whole point of this experiment, besides just “for science!” of course, was to see how black bean dye might look on my own handspun wool. Now I think I have my answer!

Final notes

*The pH of your water will affect your the final color of your yarn even if you do exactly what we did. I did some research and found out our tap water is rather alkaline, with a pH close to 8. The second blog I mentioned above shows how acidic water might yield something closer to green. If you don’t know what pH your tap water is, you can use the red cabbage test to estimate it.

*Natural dyes like black beans won’t work on man made fibers like acrylic yarns, so make sure you know the fiber content of your yarn!

*Safety first! Cover surfaces in newspaper to prevent stains, and if using a mordant other than alum, read over all precautions about handling it properly.

*There are a ton of resources out there on natural dyeing in general. But if you’re like me, you might find yourself overwhelmed by all the information, especially when everyone has different ways of doing everything! Not to mention it feels like if you mess something up, everything will be ruined.  This added to the fact that the process takes a few days means it can easily become stressful. So give yourself plenty of time and go easy on yourself if you make some mistakes. Try to enjoy whatever outcome you get. And if if anyone has knitting pattern suggestions for 4 ounces of yarn or less that look good in varied shades of blue, send them my way!

**UPDATE FEBRUARY 2013** Here’s what I knit with these mini skeins of blue: an ombre cowl!


For more on this project, check out this post!

**UPDATE MARCH 2014** Several people have asked me how colorfast this yarn is—that is, does it fade badly over time? Here’s what it looks like two years later:

2014-03-24 10.46.27

As you can see, the lightest sections of yarn faded the most, while the darker ones retain more of their blue color. Now the yarn is more of a slate blue-grey. I still love it!


36 responses

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  2. Thank you so much for this! Your four ounces would make beautiful baby booties. I am taking the masters spinners level 1 class from Olds College. We have to use 10 natural dyes for a portion of the homework. I am definately going to use this recipe. Can’t wait!

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    • Thank you! I haven’t really tested the light fastness of the yarn, and I’ve really only worn my cowl from it in winter. I have read that it’s the mordant that really affects light fastness, and alum isn’t as light fast as other mordants. However, it was the easiest and safest one to use, and it will be more light fast than no mordant at all.

  4. Mine turned out green! And not even a pretty green, a dull gray green. Soaking in vinegar now, just to see what happens. May end up over dyeing it. 😦

    • Heather,
      Hmm, my two best suggestions are to make sure that none of the bean particles are making their way into the dye water, and to try using a different water source—my water is very alkaline, and I’ve heard acidic water tends to create green hues (see
      Personally I’ve been trying to figure out how to get a natural green dye of any shade! Green seems to be almost as tricky as blue to get right.

      • I just came acrossed this, as I too would very much like to get a good blue natural dye. I am very excited about trying this one!! Thanks for the info on the ph levels also. We have very high ph water, so this could be making a difference for me. Nettles make a really soft green color. Just did a batch of alpaca/wool blend and it is quite pretty-muted.

  5. Hi!
    I did a cold water soak with bean juice for 48 hours, in a sealed glass container. Last night the juice started bubbling out? It’s not very warm here in Oregon, so I’m confused as to why it’s fermenting. And my yarn turned that purple color in your photo–although a bit deeper. Wondering if exposing it to air changes the color? So curious!
    Anyways, thank you for your post!

    • That is curious! How long did you soak the beans in the water to make the dye, and were those containers sealed too? I noticed that the longer the beans soaked the more the more they smelled, so it might be a contributing factor, along with any bean particles that made it into the dye. Good luck with your yarn!

  6. Thank you for being so thorough! I had some of the some questions about ratios and timing. I did want to add, though, that alum IS toxic in higher levels and can be irritating to the skin but is considered safe in small amounts. It’s what canners use to keep pickles crispy.

  7. Hi! I am from Panamá and i was just looking for something local to dye naturally blue and you are the shine! I am just wandering, i just want to dye cotton.. yarn is to hot for this climates. Do i need to use creme of tartar? and do all this procedure.
    Normally I used turmeric and achiote and i use alum and the natural dye all pack together for my dying no separated steps.

    will aprecciate your insights

    hasta luego guapa!

    • Hi debora,

      As I understand it, the creme of tartar helps the alum to not feel as “sticky” on the yarn and the dye to absorb more evenly. It’s not required but it has benefits.

      I’d love to see how your cotton yarn turns out with black bean dye! I’ve heard cotton absorbs natural dye differently. (This webpage has a good comparison of wool versus cotton in natural dyeing: You might end up with a different shade of blue or a even different color!

  8. I love your post 🙂 It’s a bit funny because I did the experiments one black bean with Cecile from Ways of the Whorl (the post you refer to) gosh back in 2011. I love how this is so circular. Now I am reading your fab post to help me recreate the experiment. BTW I love your picture of the cowl two years later. I have recently had several people tell me that this and that is not colourfast, but the truth I think is that no dye (even synthetics) are colourfast if you leave them in the wrong conditions. I thing that this is the charm of natural dyeing. If the colour starts to fade or change, maybe you will love the new colour even more or perhaps you can overdye and get a third colour. It’s all just a fun experiment, and I love it.

    Eddie from Eddie’s Room (

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  10. I am in th middle of dying some wool and can’t wait till tomorrow till I can take it out. Wondering though why it doesn’t get heat set like so many other dyes? Would simmering it for an hour have the same effect as the 48 hour soak? And maybe make it more colorfast? I just started another batch of beans soaking and thought that maybe I would try that method?

    As a science teacher I really like your scientific method… Thanks

    • I would not use heat with this dye, as it is extremely sensitive to temperature and pH changes. If you look through the ravelry discussion thread, you’ll notice that dyers who used heat tended to describe their results as being grayer and paler and not very blue.

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  13. HI I just wanted to thank you for your post. This project made for a great homeschool experiment. We have been trying our hands at natural dying for the last few weeks. We loved your blues and the second blogs beautiful green. We were actually hoping to achieve both colors. so we did the cabbage test ( great fun with the kiddos) and decided to run a batch with our well water ph of 9, sea salt ph of about 8 and white vinegar to get an acidic dye. we were initially disappointed when we got a blue and a purple so we decided to mix up a batch with soda ash we had from tye dying and it immediately turned green. So we have concluded that it is actually alkaline that causes the green.(we believe that when she added the baking soda to her soaking beans that created an alkaline environment) Now we are just hoping wool holds up to soda ash. We only put 1 tsp in 2 1/2 cups dye. Thanks for posting such a scientific tutorial which really got our brains rolling 🙂

  14. Reblogged this on Urban Meliad and commented:
    Reblogging this so that I can find it later.
    Garden plans currently include the possibility of growing “Zorro” black dry beans specifically for dying purposes, though they won’t be a priority for me. 😉

  15. About the green color: that author said get well water was acidic, and so she compensated by adding baking soda to the mix.

    Next time you feel like playing around, get a bit of bean dye in a bowl and add a splash of vinegar to it. You don’t get green. You get red! After that, add a splash of ammonia and watch it turn green. It wasn’t her well water. It was the baking soda.

    Meanwhile my first test didn’t appear to have any sediment so I skipped the “settle and siphon” step. Guess who has gray dye now? Sigh. 🙂

  16. I am trying this dye also and have read various accounts. Appreciated your attempt to keep good records and report your measurements. I read about a cool test, that I did, where you put a bit of the dye into 3 glasses. The center one you leave alone. The one on the right you add a bit of vinegar (to lower the pH), while the one on the left you add a bit of baking soda (to raise the pH). This way you can see if whatever dye you are trying is sensitive to pH. Well– yes! The acidic turned pink while the higher pH turned blue green. I’ll see what the middle dye actually does to my wool. Have 2 days to wait. I’m hoping for blue. –Lisa

  17. What an awesome idea! I’ll have to try this out. Maybe I’ll experiment with the pH and try out the green and pink versions. Think of the possibilities~!

  18. Be aware that not all black beans will give you blue. Some of them will give you browns and greys. The soak water won’t have any tint to it. My first time I got beautiful blues. The second time I got beans from a different store and they did not give any blue.

  19. I did a test skein in about February that was blue-ish (I didn’t use enough mordant, I think), and just yesterday I pulled it out and it was already smoke gray. It hasn’t been exposed to sun or wear and tear. Any idea what may have happened?

    • I recently read Chris McLaughlin’s book “A garden to dye for: how to use plants from the garden to create natural colors for fabrics and fibers,” which calls black bean dye a fugitive dye—that is, it fades over time, even without sun or water exposure. In my experience, the stronger the color is at the beginning, the less it fades to gray. I made a comparison photo of my black bean cowl in 2014 and in 2012. The lightest blue faded almost to gray there, but the deepest blue stayed more blue:

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  21. Wow thanks so much! I know that this is quite an old posting but I am so glad I found it! I have been working on getting my blue, bluer! I have been using black beans for quite a while now, but have never been super excited about how it has turned out. But I AM NOW! This batch turned out amazing! I used organic Black beans (my first time using organic ones) and soaked them for 48 hrs. I also used Alum for the first time (I skipped the cream of tartar though because I didn’t have any). Also I soaked the fabric in the dye for 48 hrs. I just took everything out and boy am I pleased! I’ll be updating the new and improved color on my website soon! Thanks again!!!!

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