This is a question that puzzles many who are searching for the most natural soap bar product they can buy.
Natural soaps contain the glycerine that was originally part of the oil or fat to generate the soap.
When the soap molecule is split the result is free glycerine and soap. There are several recipes for the making of homemade transparent soaps. These recipes all require the melting down of cured soap and adding alcohol. The simple alcohol used in these recipes vary from pure grain, rubbing, whiskey or vodka for the alcohol. For the home soap maker it is suggested that transparent soaps be made in small batches.