Sodium hydroxide (lye) is crucial in soapmaking because it triggers saponification, a chemical reaction that turns fats/oils into soap, creating a cleansing product that dissolves dirt and oil by forming tiny spheres (micelles) that trap grease and allow water to wash it away. In a properly made soap, the lye is completely consumed in this process, leaving behind soap and glycerin, with no caustic sodium hydroxide remaining in the final bar.
Key Roles of Sodium Hydroxide:
Catalyst for Saponification:
It reacts with fatty acids in oils or fats (triglycerides) to form soap (fatty acid salts) and glycerin.
Using sodium hydroxide (NaOH) results in harder, more durable bar soaps, unlike potassium hydroxide (KOH), which creates softer liquid soaps.
Ensures Safety (When Done Right):
While caustic on its own, the saponification process neutralizes the lye, making the final soap gentle and safe for skin, leaving behind moisturizing glycerin.In essence, sodium hydroxide is the essential ingredient that transforms oils into the actual soap product, making it effective for cleaning. (AI)