Have you ever wondered how to calculated how much fragrance or essential oil you need to add to your cold process soap recipe? Everyone does it differently. But according to the site Learn How To Make Soap, the amount of essential oil and fragrance oil used in soap should be calculated based on the base oil amount in your recipe and not the total amount of soap (oils + lye + water). You are probably wondering why? Well, I am not going to tell you because I do not want to spoil the surprise plus I want you to read the posting called Essential Oil and Fragrance Oil Usage Rates in Cold Process Soap. Learn How To Make Soap clearly explains what you need to do in this situation.