What is transparent soap? Transparent soap is simply hot process soap that uses solvents to dissolve the soap crystals that form allowing light to pass, therefore creating transparency.
What are transparent soaps made of? Transparent soaps are made of sugar, glycerin, and are partly soap and partly alcohol. Sodium hydroxide causes crystals to form in soap, which is why the soap becomes opaque.
In order to make it transparent, the soap has to be dissolved in enough alcohol or solvent to make the crystals so small that light passes freely through, making the soap look transparent.
There is no magic number when it comes to the quantity of solvent required. A good way to find the right quantity of solvents is to start by calculating a 60:40 soap-solvent ratio and then changing it to a 50:50 soap-solvent ratio.
In preparing soap of this description, ordinary soap is thoroughly dried in a stove, and dissolved in hot alcohol. All foreign matters not consisting of soap will remain un-dissolved, and must be removed in this case, because they cannot remain concealed by an opaque mass as in ordinary soap.
They are removed by deposition, or by a filter supported by a funnel, surrounded on the outside with hot water. The alcohol is then separated from the solution by distillation, until the residue is capable of forming a solid mass, when cooled in the metallic moulds. Transparent soap of this kind is generally too hard, and affords a lather with great difficulty.
Transparent and translucent soaps have a surprisingly long history. It was discovered at least as far back as 1789 that a transparent soap bar could be made by dissolving soap in hot ethyl alcohol, pouring the mixture into open molds to solidify, and then allowing the soap to age.
Well over two centuries later, transparent and translucent soaps make up a good proportion of soap bars sold in the marketplace. They are sold in a variety of shapes and degrees of optical clarity, and some are hand-crafted by artisans, whereas others are mass-produced by the large soap manufacturers.
However they are made, these soap bars have much consumer appeal, as clarity in a soap bar connotes health, purity, mildness, and freshness.
Content for this question contributed by Chintamani Nadkarni, resident of Strongsville, Cuyahoga County, Ohio, USA