Adding activated charcoal to soap

Ever since I discovered activated charcoal for use in cold process soap, I’ve been in love with the black it produces. It really is one of the only colourants that I know of that makes a black. I’ve tried different black mica and clays, but they all turned into various shades of grey. Activated charcoal is the way to go.

Now a little bit about activated charcoal and natural ingredients. First of all, we can all agree that most people, if not all, would consider activated charcoal natural, as do I. But I also find it a bit funny, because we probably have this picture of a romantic wood fire in our mind when we think of charcoal, when in reality, activated charcoal is produced under pristine lab conditions. You really don’t want to go grinding up bits of charred wood. You don’t know what sorts of metals and toxins are contained in the wood! No, the activated charcoal you buy has to be completely toxin-free and very safe to use in your skin care products. So phew for that!

Back to soap making. One problem I always struggle with and I know others do too, because the internet is full of questions about it, is: How much activated charcoal should I use? If you use too little, you won’t get a black. If you use too much, your lather goes grey. You really want to get it just right, and I found out some pretty interesting things about using activated charcoal.

First of all: STICK BLEND! I used the same amount of activated charcoal in both halves, but for the bottom part I used the stick blender (I think they call it immersion blender in the US?), and for the top half I just whisked it as much as I could. Look at the difference not only in colour (soap on the right) but also the soap ash on the top layer of the soap on the left. This shows that by stick blending the oils and lye are mixed together more thoroughly than just by whisking. You can also see a finger print on one side of the top half, showing that when I unmoulded these, the top layer was still a lot softer than the bottom layer and they have shrunk unevenly. This is also something to keep in mind when you do colour work in soaps and you mix the different portions to different consistencies.

I made these soaps a year ago and took the pictures this morning. I’ve taken one apart to see if there’s an actual difference between them. The top soap is the stick blended one, and the bottom one is the whisked one. Both are hard, but there is a difference between the feel of the soap and the lather as you can see. The hand whisked one is slightly slimy compared to the stick blended one, despite being both from the same batch of soap. I’m not sure why yet, but I’ll definitely look into it and post about it in another post.

Here’s another tip: don’t mix your charcoal with medium like water or oil first, just add it straight to the soap and then stick blend it to disperse it. If you have worked with activated charcoal before, you know how messy it is. So the less handling, the less the mess!

Now lets get to the important part: What amounts you should be using? To find out I made a bar with three different portions equaling to 1 tablespoon, 1/2 tablespoon, and 1 teaspoon activated charcoal per 1000 grams of oils (a little bit more than two pounds). All three portions were stick blended to a medium consistency (trace) – kind of thick but still pourable.

You can see in the picture that the one tablespoon produces a fairly dark black, but not quite black. You can add a little bit more, maybe 1 1/2 tablespoons, but I wouldn’t go over that, or else you will end up with a grey lather.

One last thing I want to share with you. Activated charcoal doesn’t just make black. You can also use it to darken other colours. Check out the soap below, which I made for one of the subscription DIY Soap Boxes. I combined ultramarine blue with activated charcoal to achieve the deep blue colour of the night sky. I’ve also tested it with purple mica and chromium pigment with similar results. I use a ratio of 3 to 1 activated charcoal to mineral pigment or mica, but with the mineral pigments giving me the better colours.

So that’s my findings for using activated charcoal. I hope this has been useful to you, and please let me know in the comments what your experiences have been with activated charcoal!

If you enjoyed this article, please consider donating a coffee, or a flat white as we call it here in New Zealand! This website is only possible due to my coffee consumption and early morning starts.

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