Black Bean Blue Stain

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Introduction: Black Bean Blue Stain

About: I am a Maker and Artist who experiments with a variety of mediums and projects. I also try to repurpose and repair as much as I can. Check out my instagram page @mitzsea_makes.

Blue ranks high on my list of favourite colours, when I learned that black beans can make blue I knew I had to try it.

I chose to stain my beech wood trestle desk legs and then finished them off with a clear latex (water based) topcoat.

Supplies:

  • Black beans (from the Latin section of the grocery, it makes a difference, more info below.)
  • Water
  • Calcium Chloride a.k.a. Pickle Crips Granules
  • Large pot or bowl
  • Paint brush
  • Water based clear coat

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Step 1: The Beans

To get the pigment from the beans is really quite simple. Get a large bowl or pot and put the beans in. Then fill up with water about an inch or so above the beans. Then just let them soak. Stir the beans every now and then to release the pigment from the beans.

Though, there are some tips to have the best results:

1. The first soak of beans will give you the darkest pigment. So be mindful of how big your project is and how much stain you will need. That will impact how many bags of beans you use.

2. The second soak will yield a weaker purpleish-brown that can work but not as dark.

3. If you want to get the pigment out a little faster, I found that gentle heat on the stove releases it.

4. My project required 10 cups or 2500 mL of the dye. This should help give you an idea of how much you may need for your project.

Step 2: Adding the Mordant

I took the time to figure out which type of mordant would yield the blue I wanted for my desk. I chose to use calcium chloride because it gave the result I was looking for.

I used a 1:1 ratio of mordant to dye. My project needed 10 cups (2500 mL) of dye to 10 tbs (142 g) of calcium chloride.

When mixing the calcium chloride in the dye I gently heat the dye to make certain that the mordant is completely dissolved. There is no need to bring it to a boil or create steam, just enough to make certain everything is dissolved.

The fun part is that while adding the mordant you can see the chemical reaction occur. The blue just becomes more brilliant as seen in the second photo.

Safety notes: While calcium chloride is used for making pickles (canning food) it puts in the realm of a safer chemical, it still requires smart handling. Such as, keep out of reach of pets and children. Don’t get it in your eyes, etc.

Step 3: The Staining Process

In the first picture is the raw beech wood before I put on the first layer of stain. The subsequent photos show the progression in the depth of the colour, until the last photo of the completed project.


Staining the wood is a simple process, just get a natural bristle paint brush and start slopping it on. I apply the mixture until the wood has that wet sheen to it. I let the sheen dry up before I apply the next layer. The wood doesn’t have to be completely dry just not shiny.

Keep applying until you reach the desired depth of colour. For my project, it took about 6 applications for each trestle to get it as dark as it is.

Step 4: Tips and Discoveries

During the process of teaching myself about making this stain (dye) I discovered a few things that you should know so your project is a success.

1. There is a difference in the colour you get from varieties of black beans. The two varieties I tried are what I am terming Latin Variety and Asian Variety.

A. The Latin Variety is what I used to stain my desk. You can see the colour in the first picture. Once oxidised it turns from that purplish colour to that beautiful blue. This is the common variety you find in every grocery store.

B. The Asian Variety can be seen in the second picture. It has an inky-blue colour but once it oxidises on the wood it turns very purple. These are the variety you can buy from your local Asian grocery.

C. Even though I used the same mordant (calcium chloride) in both bean dyes, they yielded different colours.

2. Different types of wood could change the hue of the dye.

A. All woods are going to have their own pH and chemistry which could effect the hue of the dye. It is a good idea to test your dye on a piece of wood of the same type as your project.

B. Oxidisation is a big part of the process. Though the dye may look different in the pot it will change during the drying process to that nice blue.

C. Once the unused portion of the dye turns brown in the jar, it no longer stains blue. So you need to use it right away. It doesn’t even store in the fridge.

3. Be accepting of the variations that natural stains or dyes produce.

A. This is part of the fun.

4. You can find calcium chloride in the canning sections of your grocery store.

5. Use a water based clear coating for the topcoat on your project.

A. Use your favourite if you have one.

B. A clear wax works really well with natural stains.

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    13 Discussions

    0
    Khovet1
    Khovet1

    1 day ago

    Very cool. I have a couple upcoming projects for outdoors furniture and will be trying this. Do you have a pattern for the trestles? I could use a few of those on some other projects. Thanks,

    1
    aysesevil
    aysesevil

    2 days ago

    I was about to paint a stripped mid century cabinet in my kitchen white but my heart was not in it. I am going to try your method stain it. Would I be able to use ice melt since food grade is not necessary? I will also dry it on fabrics. Thank you.

    1
    Mitzsea Makes
    Mitzsea Makes

    Reply 1 day ago

    As long as it is only calcium chloride and not potassium chloride or sodium chloride (ice melt can contain one of those three). The potassium will yield a purple with red undertones. Where as, the calcium chloride is a truer blue. Anything with sodium in it will turn the solution a yellowish-cream colour.

    0
    aysesevil
    aysesevil

    Reply 1 day ago

    Thank you much, you have saved me into falling into a rabbit hole resherching for this information.

    1
    ableabe
    ableabe

    Question 1 day ago on Step 4

    Great idea! Do you have an idea how durable or how permanent the color is? For instance against sunlight, or if you dye clothing, against washings? Thanks for the idea.

    0
    Mitzsea Makes
    Mitzsea Makes

    Answer 1 day ago

    All natural dyes will fade to a degree and that is why a mordant is used. It is a chemical added to help bind the pigment and prevent it from fading away completely.

    I have stained only furniture right now but I know that others dye their natural fibre fabrics with success and permanence. It is all about the mordant when using natural dyes/stains.

    When I am staining my furniture I always go darker and I mix some of my stain in with my clear wax to have an added layer of binder for the pigments. I give instructions on how to do this in my Black Bean Red post.

    I also have a photo of my chairs that I stained 3 years ago so you can get an idea of how long it lasts. From left to right: yellow onion skins, avocado pits, and stinging nettles.

    7E150E96-ED11-4D23-8A8C-757927D2A590.jpeg
    1
    ka3ros
    ka3ros

    1 day ago

    The color is uncommon but in fact really cool.
    Do you have an idea about the lasting of the stain? Does it change with time?

    0
    Mitzsea Makes
    Mitzsea Makes

    Reply 1 day ago

    For this project, I have only recently stained it blue so I do not know how this particular one will behave, but it is not my first naturally stained piece of furniture I have done. I have used yellow onion skins, avocado pits, and stinging nettles. In the photo these chairs have been stained 3 years ago.

    There will always be some fading of natural pigments, but adding the mordant helps bind the pigments. Also, another trick I use is I pour some of the stain into my clear wax as another way to bind the pigment. I give instructions for this on my Black Bean Red post.

    7E150E96-ED11-4D23-8A8C-757927D2A590.jpeg
    1
    lmiller50
    lmiller50

    2 days ago

    I love the blue color and the idea of using a natural source rather than synthetic chemicals but I’m concerned about how permanent the color is - whether it will fade over time and with exposure to sunlight. Has the color of your desk changed since you stained it?

    0
    Mitzsea Makes
    Mitzsea Makes

    Reply 1 day ago

    In this case I have only very recently stained this piece of furniture blue so, I do not know yet. But, I have used several other natural sources for staining furniture with success. Especially because of the mordant being added. A mordant acts as a binder for the pigment.

    Another way to make certain that there is minimal fading is to mix some of the stain in with the clear wax topcoat (see my Black Bean Red post). In the photo you can see a yellow chair. I stained that with yellow onion skins three years ago, I used a mordant and the mixed wax. I have also used stinging nettles (green) and Avocado pits (red) with good results.

    Of course there has been some fading but not so significant that the colour is gone or, too pastel.

    1
    Mitzsea Makes
    Mitzsea Makes

    Reply 1 day ago

    These are my chairs I stained three years ago. Left to right: yellow onion skin, avocado pit, and stinging nettles.

    7E150E96-ED11-4D23-8A8C-757927D2A590.jpeg
    1
    StringGoddess
    StringGoddess

    4 days ago

    I knew that black beans could be used to dye wool yarn blue, but I never thought about staining wood with it. Very cool.

    0
    Mitzsea Makes
    Mitzsea Makes

    Reply 4 days ago

    Thanks! I have stained several pieces of furniture with natural dyes. That yellow chair in the photo was stained with yellow onion skins. That is it’s colour after 3 years too!