Local Girl Scouts learned the chemistry of soapmaking during a visit to a Northwestern State University chemistry lab.
Members of the Girl Scouts of Louisiana Pines to the Gulf Council Troop 1512 made soap under the guidance of assistant professor Dr. Carol Chin, Christina Palomo, a biology major, and Debbie Smith, a member of the National Center for Preservation Technology and Training staff.
The three served as instructors for 10 fourth and fifth grade girls.
“The girls were provided with a little background on the old ways of soapmaking,” said Chin, who is joint faculty with NCPTT. “Traditionally, lye (sodium hydroxide) was extracted from wood ash. The pH of lye is very high because lye is a strong base, so the girls tested some lye prepared from wood ash and found the pH to be approximately 12. We also talked about how triglycerides, fats, are converted to soap and a byproduct, glycerol.”
Girl Scouts worked at individual lab stations, measured the ingredients and prepared their soap using the hot process saponification method, Chin explained.
They heated shortening, lye, and alcohol in a beaker using a hotplate, stirring the mixture using a magnetic stirring bar as well as a glass stirring rod.
After much stirring and heating, the mixture began to thicken and form soap.
Next the girls added flower petals, oatmeal, or tea to personalize their soap, and then “purified” the soap by adding a saturated salt solution.
The salt solution caused the soap to separate from the glycerol byproduct.
This step also helped to eliminate any excess lye.
They poured off the byproduct, rinsed their soap chunks, and took their freshly made soap home to re-melt and pour into molds.
“Soap is a household item that we often take for granted, but the girls learned that the task of soapmaking was historically a time-consuming endeavor that was necessary in order to have soap for cleaning, washing and bathing,” Chin said.
“I liked that we got to learn the formula before we made the soap,” said Girl Scout Lauren Mathews. “I had to do it twice because my first one didn’t have the right proportion of things. It was hard to do. I am going to give my soap as a present, so I haven’t used it yet. I really liked working in the chemistry lab!”