When it comes to natural soapmaking, the term “surplus fat” refers to the intentional inclusion of extra oils or butters in a soap recipe beyond what’s needed to react with lye. This is known as “superfatting,” and it’s a technique that transforms ordinary soap into a luxurious skincare product. These surplus fats remain unsaponified (more on saponification) in the final bar, offering a rich, nourishing experience that cleanses without stripping the skin's natural oils.
Superfatted soaps are especially beneficial for those with dry, sensitive, or mature skin. Unlike commercial soaps that often leave skin feeling tight or itchy, a well-crafted superfatted soap leaves a soft, moisturised feel after every wash. The surplus oils—whether it's creamy shea butter, silky coconut oil, or rich caster oil—form a protective barrier, locking in hydration and soothing the skin. This makes superfatted soaps a gentle alternative to harsh cleansers and a wonderful daily indulgence for all skin types.
Beyond their moisturising qualities, superfatted soaps also help support the skin’s natural barrier function. By maintaining the skin's lipid balance, they can reduce irritation, improve resilience, and even support healing in compromised or inflamed skin. For anyone seeking a soap that truly nourishes while it cleanses, superfatted bars are a beautiful, skin-loving choice that blends artisan tradition with botanical care.