Everybody is talking about essential oils (EO's) in soaps. Frankly, I'm skeptical. As a certified aromatherapist, I am aware of and a student of the benefits to be found in the use of EO's. But in cold process soap? Hmmmmm. Here's why.
When you combine a sodium hydroxide (lye) solution with oils to make soap, the temperature rises to well over 180 degrees and the pH goes up to around 14 (the process is called "saponification"). I have not seen any studies which confirm that essential oils stick around under those conditions. So my theory is that if the aroma of the essential oil remains after saponification I will use the essential oil in soap making. I haven't found too make EO's that do.
Another consideration is the cost. EO's are REALLY expensive.
So the EO's I use are reasonably priced and the aroma of the EO remains after saponification. I use some citrus oils and Rosemary (Rosmarinus officinalis), Tea Tree (Melaleuca alternifolia), Lemongrass, (Cymbopogon flexuosus), and Spearmint (Mentha spicata).
So while I make no claim that the reported health benefits of these EO's can come from my soaps, I know that your skin will love them!