Sometimes you'll want to add a little extra something to make your soap a bit fancier. Any other element added to the liquid — such as plant material, minerals, or mineral pigments used as colorants — will show up in the finished soap in a variety of ways. Some plant matter acts as a natural colorant. Minerals from hard water show up on the surface of the soap as harmless “ash.”
If you're using ultramarines or oxides to create a solid color, you can add it right from the start. These mineral pigments stand up perfectly well to the lye, and by making a tinted lye solution, you don't have to worry about specks of undissolved pigment in the soap.
To get the properties of herbs into your soap, infuse them into water or oil. What does that mean? You simply place the herbs in heated water or oil and allow them to steep — like you're making hot tea. The scents, colors, and beneficial properties of some herbs are strong enough to survive the soapmaking process, but other herbs are not. This is something you'll have to discover for yourself. Many natural soapmakers rely on herbal infusions to create their soaps and find that the properties of the herbs come through beautifully. (For information on how to make herbal infusions see Chapter 4.)
Certain spices release a great amount of color into the solution. Sometimes the lye infusions smell pretty bad, but the scent goes away in the finished soap. Use finely powdered herbs or soft-leaved flakes in this application, as they will be in the final soap and large hard pieces will scratch.
How to Handle Infusions
Use the infused water just as you would regular water. If you want the texture of the plant material in your soap, don't strain out the herbs before using it. However, there are some herbs that are scratchy on the skin, so be sure to strain these well before using.
You can infuse the liquid oils in your soap recipe with herbs. You'll find that some herbs release their color into oil better than into water. Use the infused oils as you would regular oils. Use your infused oils right away as the plant matter you've added to it, even if you can't see it, will rot, making the oil unusable.
Since you'll need to heat the water to make the infusion, be sure you allow time for the infusion to cool before mixing it with the lye. Remember to use room temperature or colder water to make the lye solution. Depending on the strength of the infusion, adding the lye to it may make it a strange color with an equally strange odor.