Xiangbei explained her plan to Grandpa Tong, expressing her intention to entrust the soap-making task to Tong Xi and seeking his guidance to turn it into a thriving business. Grandpa Tong readily agreed, quickly preparing various recipes and herbal solutions for the endeavor. Tong Xi, despite her somewhat delicate appearance, was well-versed in medicinal herbs and martial arts, having been raised with herbal baths and trained by Mrs. Ding Shan. Grandpa Tong harbored hopes of nurturing her talents and perhaps sending some of the children out of the mountains for a better life.
The soap-making process involved adding colors, fragrances, herbal solutions, and creative touches to the basic soap-making foundation. Tiger, who returned with lime, wooden tubs, and bamboo bowls, immediately set to work listening to instructions for making lime milk. Jingjing was tasked with collecting leftover fats, oil membranes, and tendons from hunting, which were then processed into oil in the adjacent room.
Tong Xi used a small charcoal stove to dissolve alkali crystals into a saturated brine, while North handed her a long-handled spoon to slowly pour the lime milk into a large basin for settling. This process, known as causticization, involved mixing soda crystals (sodium carbonate) from natural alkali pits, commonly referred to as soda or baking soda, with lime milk (calcium hydroxide). The resulting solution contained caustic soda (sodium hydroxide) and hydrated soda ash.
North placed another empty pot on the ground, supported by a wooden bucket. As the fat pot boiled, releasing oil, North cleared away floating debris and foam, scooping out the clear oil and adding it to the pot. Simultaneously, she poured the alkali solution into the hot oil, stirring clockwise at a consistent speed for about half an hour until the oil began to cloud, indicating the saponification process. Only then did she start scooping out portions and adding them to wooden molds.
A group of children, each holding two wooden boxes, added various ingredients like sulfur or medicinal solutions, flower petals, or light plant-based dyes to their boxes. When North poured the soap solution in, they all stirred the contents with both hands, ensuring an even mixture. Then, they set the boxes aside to start the next batch.
Tong Xi brought several small medicine stoves, continuously boiling water for infusions like rose and chrysanthemum, producing fragrant scents, as well as pine needles and fragrant leaves for a plant-based aroma. Additionally, there was the herbal scent of anti-itch potion. Pomegranate seeds were also boiled to extract fresh, slightly sweet juice. North poured the soap solution into several wooden basins, having Tong Xi mix the boiled infusions in a 1:1 ratio with a couple of spoonfuls of green oil to create a blended paste. This became the semi-finished product for shampoo and shower gel, filled into bamboo tubes or ceramic jars.
Once all the containers were filled, North added saturated saline solution to the remaining soap solution in the large pot. After boiling and letting it sit for a couple of hours, the soap solution and glycerin separated into layers. North then scooped out the soap base, leaving it for the next time to directly process and make decorative soaps or shower gel.
Clapping her hands, North said, "We can consider this a success. When they harden by themselves, we can come back tomorrow to cut and package them. Alright, let's go eat now. If there's anything you don't understand or want to ask, we can discuss while eating. After the meal, we'll harvest honey from the beehives!"
"Wow! Wow wow wow!!!" The group, previously silent and focused on their tasks, erupted in excitement, rushing to the dining room.