How to Add Glycerine to Liquid Soap
- 1). Remove the methanol by boiling it off the glycerin byproduct. For liquid soap, use a catalyst of potassium hydroxide (KOH).
- 2). Heat the byproduct until it reaches betwee 113 and 122 degrees Fahrenheit. Add the lye to the water, and then add the lye water slowly to the byproduct, while stirring slowly. The proportion of lye is important to get the consistency of soap that is not too harsh on your skin. The amount of lye will consist of multiplying by 1.52 (with 92 percent KOH), 1.56 (with 90 percent KOH) or 1.65 (with 85 percent KOH).
- 3). Mix the glycerin, lye and water for 10 to 15 minutes, maintaining a steady temperature throughout (between 113 and 122 degrees Fahrenheit).
- 4). Cover the mixture, leaving a small air gap. Let the mixture cure for two weeks. If the soap is gelatinous or sticky, slowly warm it on the stove while adding water gradually until the temperature reaches 113 degrees Fahrenheit. At this point, the impurities should be eliminated, leaving 80 percent to 90 percent pure glycerin.
- 5). Add a small amount of the glycerin to liquid soap or shampoo, approximately 10 to 20 cubic centimeters per 500 cubic centimeters of soap or shampoo.
- 6). Add any essential oil you desire to add fragrance to the soap. (This is optional and is for fragrance purposes only.)
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