What type of olive oil works best?
Refined A, Extra Virgin and Pomace Olive Oils each produce wonderful Castile soap bars. Make sure to buy your olive oil from a reputable company to ensure it is 100% pure olive oil and is not undercut with cheaper oils. We found that Refined A Olive Oil produces the whitest soap, Pomace Olive Oil produces a lovely creamy white and Extra Virgin Olive Oil produces a slightly yellow soap. Pomace Olive Oil comes to trace in a relatively normal amount of time, but Refined A and Extra Virgin Olive Oil both take longer to reach trace. Consider price as well. In today's market Pomace is the least expensive while Extra Virgin is the most expensive.

Pictured: Pomace Olive Oil.

Should a water discount be used?
Most cold process soap recipes are balanced with solid and liquid oils to produce a well-rounded soap bar; Castile soap is the exception to the rule. Olive Oil is unique because with time, it can produce a solid bar despite its liquid oil makeup, but it does take time to become hard. This initial softness makes unmolding difficult, which is why most Castile soap is made with a water discount. Using a heavy water discount contributes to a harder bar faster, making the soap easier to remove from the mold. We used a water to lye ratio of 1.5 parts water to 1 part lye (Water : Lye, 1.5 :  1 in the pictured soap). We have found the water discount alone to be enough to produce a hard bar, but some soap makers also include sodium lactate. We recently made a few batches of Castile soap and were able to easily unmold and cut the soap after a couple days, but it could take up to two weeks for the soap to be hard enough to unmold and cut the soap.

How long does Castile Soap take to cure?
Cure time, the time needed for soap to reach its full potential, takes much longer for Castile soap. Most normal cold process soap takes 4 to 6 weeks to cure, but Castile soap takes months to cure. Once cured, the soap's pH has reached its optimal level and the bar is firm and long lasting. Castile soap with its liquid oil makeup takes at least six months to cure, but we recommend one year for best performance.