The science of soapmaking

01 / Why oils are starting materials, not the finished cleanser

Many natural oils are composed largely of triglycerides: molecules in which three fatty acids are attached to glycerol. Their relative fatty-acid composition influences the properties of the soap formed. Coconut and palm kernel oils tend to be richer in shorter saturated fatty acids than olive oil, while castor oil is notable for ricinoleic acid. The outcome depends on their blend, not on one oil in isolation.

02 / The difference between NaOH and KOH

Sodium hydroxide and potassium hydroxide are both strong alkalis used in soapmaking. Sodium fatty-acid salts generally support more solid forms, while potassium fatty-acid salts are often more soluble and useful for traditional liquid soaps. Correctly calculated quantities and suitable processing are necessary to avoid excessive caustic alkali.

Simplified reaction: triglycerides + potassium hydroxide → potassium fatty-acid salts (soap) + glycerol.

03 / The reaction changes the materials

When the ester bonds in triglycerides react under alkaline conditions, glycerol and new soap molecules form. This is not the same as emulsifying oil in water, and there is no reason to assume the original oil remains unchanged. If a formula deliberately retains an excess of unsaponified oil, the final composition and claims must reflect that; the pictured Luma Castile Soap label states no free oils remain after saponification.

04 / Processing, dilution and quality controls

Finished potassium soap may require dilution and further adjustment for concentration, clarity, handling and stability. Relevant quality checks may include appearance, batch consistency, alkalinity and excess-free-alkali assessment. Cold-related cloudiness can occur; the finished product should be evaluated rather than judged solely by transparency.

05 / Why pH matters—but does not tell the whole story

Traditional soaps are generally alkaline; attempts to force them to substantially lower pH may alter solubility and change fatty-acid salt behavior. Mildness and suitability also depend on the overall formula, how much cleanser is used, contact time and individual skin condition. Synthetic-detergent cleansers may permit different pH targets.

06 / What this means for the wider Luma collection

Saponification explains true soaps, but it is not the process used to make every botanical item. An anhydrous hair oil, for example, involves oil selection, blending and stability considerations rather than conversion into fatty-acid salts. Each Luma product page will distinguish its own ingredient story and production method.