When making soap I like to keep the ingredients as natural, local and earth-friendly as possible. I generally choose to use essential oils rather than fragrance oils and try to source local products such as rapeseed oil and herbs. Though one of my greatest challenges is finding natural ways to colour my soaps without using artificial ingredients.
Conventional soaps are coloured with an assortment of chemicals - even some which are coloured "naturally" are often tinted with pigments such as oxide powders which are created in the laboratory rather than mined from the earth. I'm not sure which one of those sources is worse though! Other conventional colouring methods include the use of liquid dyes, micas and even food colouring - all of which can produce lovely soaps but are not necessarily ingredients you want to put on your skin.
There are lovely herbal and flower infusions (teas) that can help give colour to your soap base though: I use goldenrod and calendula for yellows and alkanet for violets. Honey added into your lye water can give a warm camel brown and chai tea leaves can bleed into beautiful brown specks throughout your bars. But the biggest challenges for me are are blues and reds.
This week I've experimented with two new natural colours which haven't quite given me the tints I was originally after but still led to shades which I think are beautiful. The two new ingredients are woad and madder root powder.
Woad has been used for hundreds of years in the dyeing of cloth and wool and even in native British tribal decoration. Remember when Mel Gibson painted his face blue in Braveheart? That's woad! It keeps secret its vibrant blue personality as a plant though - it looks rather like goldenrod and extracting the blue powder is a time-intensive process. Even so, a textile artist in our allotment grows some on her plot and I've already purchased seeds to grow my own next year. For the soap, I added about 1/8tsp of woad powder to a 400g recipe which uses oils that are primarily yellow. Though I'd hoped to get a blue out of that I was instead rewarded with a gorgeous green-blue - obviously due to my oil colour. The soap that I allowed to go through gel phase turned out much deeper in colour than the non-gelled but I think I can find purposes for both shades. To get a more blue colour I imagine that I'll just need to up the amount of woad powder.
Madder has also been traditionally used in the dyeing of wool, but in achieving a crimson red. I have some seeds for this plant as well but am a wee bit hesitant about sowing it in my garden due to tales of its invasive habits. The roots of the plant are what provide the colour and when ground up they can either be used to infuse oils or be added in to the soap recipe directly. I opted for the second method in my experiment and ended up with a soft feminine pink for the un-gelled soap and a deep salmon colour for the gelled. This time I used 1/4 tsp of the powder and added it to the soap before trace. Though the un-gelled soap was a bit sticky in getting out of the mould, if I'd have left it another day or two it would have come out whole.
I'm quite happy with the results of both these natural ingredients and will definitely be adding them to my must-haves for soap making. If you come across any and want to give it a go I'd love to hear about your experiences as well.