There was a time when bar soap sat proudly on every sink . You may have seen the oval soap, placed on a wall-mounted soap dish in schools (which is making a comeback) or left to dry in the family bathroom.
Then, in the 1970s and 1980s, solid soap began to give way to liquid soap, which became the new standard. It appealed with its generous lather, more visual than beneficial, its exotic and colorful fragrances and bottles, its modern image, and its practicality. Solid soap gradually became outdated, deemed impractical and even falsely unhygienic.
But beneath its sensory and practical appearance, traditional liquid soap has many flaws. - It is composed mainly of water (up to 80%) and requires the addition of often synthetic preservatives to prevent the proliferation of bacteria. - It contains sulfated surfactants (such as Sodium Laureth Sulfate) or other synthetic surfactants and emulsifiers (on the INCI list some generally begin with PEG) which are powerful, very foamy but can be irritating to the skin and not environmentally friendly. - It is packaged in plastic which is rarely recycled and difficult to recycle. - Finally, it is less economical than a solid soap: a 250 ml bottle is on average equivalent to a 100 g solid soap, for a higher cost and ecological footprint.
Solid soap: a beautiful, useful, and responsible choice. Driven by environmental concerns and the need for more respectful, yet simpler products, solid soap has been regaining its former glory in recent years. We're (re)discovering the beauty of the gesture, this invitation to take care of ourselves and adopt a more conscious ritual. It has also been demonstrated by the WHO, during the pandemic, that solid soap is just as effective as liquid soap.
But you still need to know which solid soap to choose... Because not all solid soaps are equal!
There are two main types of solid soap:
Hot saponified industrial soap . It is the most common, found everywhere, even on market stalls. It is easily and widely produced from standardized soap balls. It is cooked at a high temperature (around 120°), which destroys the natural glycerin and denatures the ingredients. Its formula is generally composed mainly of palm oil or other hydrogenated vegetable oils (INCI: sodium palmate or sodium palmitate hydrogenated ), it very often contains controversial preservatives (like the tetrasodium EDTA), synthetic dyes and fragrances . How to recognize it? It is hard, highly perfumed, and precisely molded. It takes all shapes. Its price is not a guarantee of quality. Read the INCI list (mandatory) if you have any doubts.
Cold-process solid soap. It is made without cooking, using a slow, artisanal process. Naturally superfatted, it leaves a soft, protective film on the skin. It is naturally rich in vegetable glycerin, not artificially added. Unlike the hot-process method, cold-process soapmaking preserves the properties of vegetable oils, which are rich in nutrients and active ingredients and naturally rich in glycerin. How can you recognize it? By its shape, which is never perfect, and by its creamy texture, if it is well-made. What makes the difference between different cold-process soaps? The choice and quality of the selected oils and raw materials, the sensoriality and refinement of the texture and fragrance, and the final result on the skin make all the difference. Once again, read the mandatory INCI list. Finally, note that from July 2026, all solid soaps must be packaged in a case for hygiene reasons.
At Domaine Singulier, we've chosen the demanding path of cold-process soap to offer an exceptional soap that's sensory, natural, cleansing, and caring. We use pure, high-quality organic vegetable oils, free from palm oil and derivatives. Our formula is 100% natural. Its exclusive recipe is handcrafted by an excellent manufacturer based in southwest France. Its natural fragrance was composed by a master perfumer for a refined and subtle olfactory result. The result on the skin is exceptional. And of course, each of our soap formulas complies with European regulations (EC No. 1223/2009), the strictest in the world.
To go further
☞ learn more about cold saponification
What about reconstituted soap powder? A new zero-waste trend, homemade soap powder is a mid-range alternative. Its main advantage? Lightweight packaging (less water, less transport impact). Once reconstituted, it transforms into liquid soap. But not all formulas are created equal. Some contain surfactants that can be irritating and aren't truly natural. Read the INCI list, which is always mandatory.
What about traditional Marseille soap? Cold-process soap should not be confused with Marseille soap. Marseille soap can be artisanal or industrial. It is made by hot saponification, using a cauldron process. The paste is cooked for several days and then rewashed to remove excess lye. Glycerin is added. It is especially ideal for laundry and household cleaning. It all depends, of course, on its formulation and the ingredients it contains.