Lovehound said:Castor contributes something that I haven't seen in any other popular base oil: ricinoleic acid. I haven't checked that no other oils have it, but of the oils I stock only castor has ricinoleic. I believe this fatty acid is responsible for castor's popular lathering and conditioning characteristics.
Woodi said:I use 3 to 5% castor in my soap recipes. Beyond 10% the soap feels sticky to me. Castor is supposed to help retain scent in the soap too.