Testing Natural Green Colorants in Cold Process Soap

I use natural colorants in my soap, as much as I can. Things like turmeric and paprika can make excellent soap colorants and they are easy to find, economical and have the benefit of being natural (for those of us who prefer that). But some colours are hard to come by in the natural world: blues, purples and even true reds (read about my misadventure using rose hip powder here). I still haven’t been able to find indigo in stores, and certainly not online at a reasonable price. [I have since found it at Maiwa] The colour green falls somewhere in between. [ Read part 2 of this green colorants experiment here ]. On one hand it’s very easy to find green tea and spirulina, but on the other it can be difficult to predict how these organic materials will react to lye and a long cure. Usually clays are very reliable since they are not vegetable matter and so are more stable. But green clay isn’t really green. And as I just found out, many clays sold as colorants are actually mixed with micas or oxides (French pink clay, Brazilian purple clay).

Last week I saw a bag of green powder at my local Middle Eastern grocer. The kind store owner was surprised and delighted that I knew about carete, a middle eastern ingredient and apparently a favourite of hers. I didn’t have the heart to tell her that not only did I not know what it was, I planned to use it in soap (the leaves of the jute plant, or Jew’s mallow, are often used as a soup thickener in Middle Eastern cuisine). At 2.50$ for 250 grams it was worth the gamble. At the same store I had recently also purchased some spirulina and chlorella, which I had yet to use in soap. And finally, I had some dandelion leaves, which I had picked and dried myself the previous summer. I had 6 different possible green colorants and so I decided an experiment was in order! An experiment to test six powdered ingredients as soap colorants: green clay, chlorella, spirulina, macha green tea, dandelion powder, and jew’s mallow.

I decided to use a muffin silicone mold with six cavities, and a 14 oz Bastile recipe. I would leave it unscented of course and would have to measure it in grams because it’s important to be precise with small recipes like this. Usually we are told to use 1 tsp of colorant per pound of oils, but I decided that if I wanted the differences to be apparent I would have to increase that ratio to 2 tsp/lbs of oils. I calculated that each cavity would hold 14 oz/6 of oils = 2.33 oz of oils which is 6.8th of a pound. 2 teaspoons is 9.8 ml, almost 10, so I divided 10 by 6.8 and got = 1.4 ml. A quarter teaspoon is a bit less than that, so I decided to use quarter teaspoon. My hypothesis was as follows:

  • That chlorella and spirulina would come out looking the same: a darker mottled green. Possibly speckled as well and possibly not very green. I did not think that the blue-green of spirulina would actually be visible.
  • That the green clay wouldn’t look very green at all, but instead, kinda grey.
  • That the dandelion powder would be the most yellowish of the bunch, speckled as well.
  • That the matcha green tea would be the punchiest of the greens, not speckled or mottled. The ideal colorant in other words.
  • That the Jew’s mallow would do one of the following: 1) thicken the soap batter and possibly burn during forced gel. The fact that it’s used to thicken soups worried me a bit because starch means sugar and sugar means heat. 2) Come out looking like the dandelion soap, another leaf, but less mottled.

My final hypothesis was that all colorants except the clay would look some shade of green; that all the colorants except the matcha and the clay would have some form of speckling effect, because the powders are still broken down vegetable matter, but the green tea is made of tender young leaves and is therefore more powder-able. Finally I also expected to be most impressed with the macha. Here is what happened.

I premixed the colorants with some of my oils, then brought my soap batter to light trace and measured equal amounts of soap into 6 containers and added the colorants. I was happy to see that I had calculated the amount of soap correctly and each muffin cavity was filled to capacity. From top left to right, and bottom right to left: Green Clay, Chlorella, Jute Mallow, Dandelion, Matcha green tea, Spirulina.


At this point, I had high hopes for the matcha: that green is spectacular. I put the muffin tray into a preheated oven for about 2 hours, then when I started seeing alien brains on the jute mallow soap, I opened the oven door to cool it down a bit. Eventually all the soaps except the clay soap developed mild alien brains.

In the end this is what happened:


  1. All of them except the clay developed some form of alien brains in my heated oven.


    Jute or Jew’s Mallow Soap: overheated during gel phase and developed alien brains.

  2. The matcha was really disappointing. It turned from the brilliant green when wet to a muted darkish green to brown – not a nice shade of brown either. I’d be curious to see how it performs in hot process soap.
  3. The green clay stayed stable, as expected. Not grey though, more of a tan colour. A stable non-colour essentially. Like Joni Mitchell said: “constant in the darkness – where’s that at?”
  4. The spirulina and chlorella looked almost identical at first, but after a few days, the chlorella started taking a  yellowish, faded tone, while the spirulina stayed on the bluer side of green. I guess this makes sense, since spirulina is blue-green algae. Surprisingly, the chlorella also got pock marked! Here’s a closeup:


    Notice the pock marks and yellowish tone in the chlorella soap…

  5. The jute mallow also got pock marked. From over-heating I suppose, which I had suspected would happen due to the starch. But overall, it performed really well. The tone is nice, if a bit subdued, but provides a nice natural-looking green. Best of all, it has stayed that way, and after a two month cure has barely changed.
  6. The dandelion was the most mottled, as expected since it wasn’t as fine a powder as the jute mallow or matcha. However, it is also the most stable of the plant colorants. This was really surprising, and now two months after the experiment, the dandelion soap still looks the same shade of green and hasn’t faded or turned yellow. It is also, in my opinion, the nicest shade of green. But alas, it’s mottled and not a solid colour. The dandelion also happens to be the only one I didn’t pay for. It was “wild crafted,” as they say.

Here they are at the six week mark. The difference between spirulina and chlorella is more pronounced than it was after a few days, the matcha is browner and the dandelion, jute (as far as I can tell) and clay are the same (!).

Natural-green-soap-colorantss-6wk-cure-mars-balms (2)

And lets see what they look like inside:Natural-green-dyes-6wk-cure-inside-marsbalms In conclusion, out of these six materials, I’d say only four qualify as worthy green soap colorants: chlorella, spirulina, jute mallow, and dandelion leaves. The superfine french green clay is a nice soap additive, but as a colorant produces a tan, not a green, colour. The matcha green tea makes soap green for about five minutes, then turns brown. Spirulina beats chlorella as a green colorant but not by much, and while both are worthy soap colorants that produce solid green tone, they lose points for fading and turning yellowish. Jute mallow is a new discovery for me, as a food and possible soap colorant. I have never heard of anyone using it to colour soap so it was nice to see it perform so well. Just beware of overheating. Ironically, my handpicked bunch of weeds – what some people pay and work so hard to get rid of – has to win this one. I have never heard of anyone using dandelion leaves to colour soap either, but it was an idea that paid off. In spite of the mottling, I find that dandelion produces the nicest green tone, which is surprisingly stable and doesn’t give off a smell (unlike the algae, which do).

Doing this experiment was so much fun, and I can’t wait to do another one. Thanks for reading 😀

What do you use to colour your soap green? Have you used any of these materials before in your soapmaking? I’d love to hear your stories.



23 thoughts on “Testing Natural Green Colorants in Cold Process Soap

    • marsbalms says:

      Thanks 🙂 I like the chlorella as well, I’m curious to see if it will change any more. I’ve never tried alfalfa or parsley, but that would have been a good thing to add. Maybe another experiment is in order 😉 I know Brambleberry has a zeolite clay that’s a darker green than the french green clay, but I’m not sure if it’s a mica or oxide blend.

      • islandsoapster says:

        I have observed that chlorella changes just a little, to a more forest green, but it’s still the closest I’ve ever got to a lime green. The green zeolite clay looks a lot like spirulina to me. And as far as I know it’s just zeolite clay.

  1. marsbalms says:

    Yes, it definitely looks like it’s heading for lime green. Have you noticed a difference in the color if it’s non-gelled? I should have done two batches and kept one in the fridge. Yup looks like the zeolite clay is pure clay, so that might be interesting. I just love clays as colorants, because they don’t change.

  2. Amanda says:

    For the dandelion leaves, did you dry them out and then grind them up? It’s a great and free idea for colour and I would love to try it.

  3. laura staley says:

    I picked, dried, and ground clover {the heart-shaped leaves) to use as a colorant. It started out bright, but faded to an ugly olive. I am going to try parsley. Picked up some chlorella at Lucky’s Market when they opened here, and my Google search on how to use it in CP soap brought me to your blog. Thanks for the info!

    • marsbalms says:

      Hi Laura! I’m glad you found the info helpful 🙂 Let me know what you think of the chlorella. I’ve used it twice and both times I’m kind of disappointed in how it turns a bit brownish. I just made another batch of soap samplers this week and decided on dandelion for my green. It was the first natural green colorant I ever used, and it’s still the one I prefer. It hasn’t faded on me yet, and I have no idea why. All other leafy greens seem to turn brown. Thanks for telling me about the clover, it’s very interesting to hear about 😀

  4. Ernestine says:

    Just wondering if anyone here has used milk thistle powder as a colorant… and if so – what color did it turn? Trying to make some all natural colored soaps using just herbs and spices (naturally occurring that is)

    Thanks much in advance for any help you might be able to offer. Great site btw – VERY helpful.

    • marsbalms says:

      Never tried milk thistle, but I almost tried yarrow the other day. I have heard that yarrow makes soap kind of yellow though. I also wanted to try neem powder, which is easy to find, affordable and has some very interesting properties. My general observation is that herbs all turn brown. The only one that hasn’t turned on me (lol) is dandelion. I’d like to know why, maybe it’s the bitterness or something to do with the milkiness. Maybe milk thistle would act the same way? If you try it, let me know, I’m very curious now. I’ve never seen milk thistle powder available anywhere. Where do you get it?

  5. Sheri says:

    So glad to have found This! Guess I’ll put the matcha back in the cabinet, it is definitely not the color I want to use for my avocado soap

  6. Amber B. says:

    Awesome experiment, thank you for paving the way for fellow soap makers when it comes to these natural colorants! I have found dried, fine-ground parsley to be another great colorant in soaps! Just like the dandelion in your experiment though, it leaves the soap speckled due to not being able to get a fine enough grind, as well as its inability to dissolve fully in liquid. I’ve always enjoyed the speckled look however & think it adds a rustic charm! It’s also one of those natural colorants that stays fairly true through cure… It’ll fade to a more muted green, but won’t morph to brown & is still quite lovely at 6 weeks & beyond. I imagine one could try an infusion with one of their liquid base oils to avoid the speckled look parsley imparts, but I think the green produced this way would be considerably lighter & muted in comparison. This was an EXCELLENT experiment & I thank you for sharing this & being so thorough! I was looking to see how matcha powder would behave in CP & you answered my question perfectly!

  7. Deb Hohenstein says:

    I recently infused 5oz of olive oil with two sealed tea bags of organic dandelion leaf. My 1 pound experiment base has been used before and it called for 6oz of olive oil so I added one ounce to the 5oz of infusion and used it all. This was different than before. I only added some infusions to bases, never this much.
    Also used .5 oz AuraCacia lime essential oil. Refused to trace. Any thoughts?

  8. SHA says:

    My experience with natural colorants (which I love using!) has been that plant-based greens eventually fade to brown/olive.

    My track record with French Green Clay has been more satisfying than you experienced, maybe because I generally use more. When I use 1 tsp per pound oil, I get I nice dusty green. With 1 1/2 tsp ppo, and forced gel, the colour is better. 1 Tbsp ppo gives an even nicer green.

    I loved seeing your colour results with the different colorants! Thank you!

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