When making soap from scratch, it's important to avoid adding essential oils (EOs) until near the end of the process. Otherwise the lye--an unavoidable ingredient in soap recipes--will destroy both the fragrance and the healing qualities of the oils. While essential oils can be added by themselves at the end stage, adding them to a carrier (base) oil first gives the soap maker some advantages. First, the base oil adds extra moisturizing properties. Secondly, EO cannot be applied directly to the skin, so it's difficult to test the scent on yourself without blending it with a base oil first.
Plan your blends before starting the soapmaking process.For every ounce of carrier oil you prepare, you'll be adding up to a tablespoon of essential oils. For a 2-pound batch of soap, up to 2 ounces of a carrier oil-EO blend is about right.
Select your carrier oil. When a small amount of base oil is added after the lye has been neutralized, the process is called superfatting. Common oils for superfatting include olive, jojoba, almond, castor, wheat germ, avocado and apricot.
Blend your essential oils. You can use one essential oil or a combination that pleases you, but if you use two or more EOs, blend them in a beaker or jar with an eyedropper, adding new scents drop by drop until you attain the fragrance you want.
Add the essential oil to the carrier oil.
Follow your soap recipe and wait for the stage known as "trace." Dip a spoon into the soap pot and trail some of the mixture across the surface. If it forms a raised line, your soap has reached trace and you can safely mix in special additives because the lye has been neutralized.
Gently add your essential oils or the carrier-EO blend. Stir the mixture completely.
If the soap mixture appears to curdle, it may be reacting to the EOs. Stir the mixture vigorously with a metal whisk.
Pour the soap mixture into greased molds and cover the molds with a towel or blanket. The soap will be ready after a minimum of 4 weeks.
Because there are literally hundreds of essential oils to choose from, the art of blending EOs can seem elusive. There is no shame in starting with a single-note soap, such as peppermint or lavender. As you get adventurous, you will start creating dynamic duos like rose-sandalwood. Ultimately, you may want to study which scents are usually considered base, middle and top notes, and in what ratio they should be blended.
Although you will only need about 2 ounces of the carrier oil-EO blend to superfat the average batch of soap, it's a good idea to make 6 or 8 ounces of the scented oil at a time to use in future batches of soap or as a massage oil.