Advanced Edition, Soap Stock

"Making soap from feces, fruit, you really can think of it. That stuff can..." Lu Zhe was surprised. The survival manual said there was really a country that used this stuff to make soap.

"Damn, it's actually...true!"

"No way?" The five girls, including Shen Bing, all exclaimed in shock!

Lu Zhe said solemnly, "In the beautiful Himalayas south of us, in another ancient civilization, they not only make soap from cow dung, but also use it to make..."

Lu Zhe waved his hand, "Forget it, that's too disgusting!"

"Lu Zhe, is this really okay?"

"My curiosity has been piqued!"

"Even though it's disgusting, just tell us the answer. Leaving us hanging like this is killing me."

The girls looked at Lu Zhe with a mixture of horror and curiosity.

Lu Zhe sighed, "The method of drying cow dung into powder, applying it to the teeth and brushing, is completely unsanitary. It's also easy to get infected with E. coli bacteria! So please don't feel curious about this anymore, okay?"

The girls were dumbfounded.

As expected, compared to India, Grandpa Bei and Grandpa De are still juniors.

At least Grandpa Bei and Grandpa De did it out of necessity to survive, but those people purely enjoy doing it that way, even when better options are available. Are you convinced or not?!

Shen Bing sighed and said, "Lu Zhe, this can't really be your method for making soap, can it?!"

"Of course not!"

"Then what is your method?"

Lu Zhe calmly said,

"Mix plant oils and animal fats, add some emulsifiers, fragrances, pigments, and finally add sodium hydroxide to trigger saponification. Finally, pour it into molds and let it sit for a month. That's the soap I want to make!"

The five girls were stunned, blinking their big eyes.

"Unexpectedly, this method is so normal!"

"It doesn't sound...disgusting at all!"

"It even sounds rather advanced."

"Are you sure this will work?"

"He definitely didn't tell us everything that's needed!"

"So in other words, there's no way we can make this kind of soap..."

Lu Zhe thought about it: "Actually, not necessarily! Let's take an inventory of our supplies and see what we're missing. We can look for substitutes."

Ning Shu thought about it: "Animal fats are easy to find, we can use bear fat or lard!"

Lu Zhe nodded: "That's right!"

Lin Qianqian said: "What about the plant oils?"

Lu Zhe picked up a palm fruit and said, "Don't we have two palm trees here with lots of palm fruits? Palm oil can be extracted from palm fruits in many ways."

Jiang Yao wondered: "Where do we get the emulsifier?"

Lu Zhe said, "We still have some dammar resin left, which is a natural emulsifier. And it's from the torchwood family of plants, so it's also a natural fragrance!"

Tang Xiaoguo said, "What about the pigment?"

Lu Zhe replied, "Unbleached palm oil itself has an auntie-pad color. The resulting soap should be a pink that girls like the most."

Tang Xiaoguo protested: "Do you have some problem with pink?"

Shen Bing thought about it: "So with everything you said, looks like the only thing we're missing is sodium hydroxide!"

Lu Zhe held out the bottle of salt in his left hand and a lemon in his right: "We have salt, batteries, how could we not have sodium hydroxide?!"

Shen Bing was surprised: "Electrolyze salt water? Will that work?"

"It doesn't cost anything to try, why not?"

"But...what about the molds?"

"That's even simpler!"

Lu Zhe took out a piece of bamboo that was originally going to be used as firewood: "The hollow cores of bamboo are the perfect molds!"

Shen Bing suddenly widened her eyes as she suddenly realized something:

Unknowingly, it seemed they had gathered all the necessary elements to make soap!

"So you mean we can make truly all-natural soap now?!"

Ning Shu thought about it: "No, I remember sodium hydroxide is a strong alkali. Wouldn't it burn your hands?!"

"The sodium hydroxide solution electrolyzed by crude methods doesn't have very strong caustic abilities, but it can still cause saponification. To ensure absolute safety, let the soap solution sit for a month after it's done, by which point it will basically be harmless to skin. In the meantime, we can use pancreatin for washing."

The girls looked at each other excitedly. Ning Shu said animatedly: "So from now on, we get to live a life where we can wash clothes and wash our faces with soap?"

Lu Zhe nodded: "Later, we can even take the finished soap, add hot water to melt it down again, mix in extracts from hair and skin nurturing plants, and make shampoo and facial cleanser."

"Let's make soap!"

"We're going to make soap!"

"Maybe when we get back, we can even open a soap factory together!"

"Where do we start, Lu Zhe?!"

"First extract the plant oils. Strip all the palm fruits off, boil to soften, then drain the water and mash into a paste with a stone mortar and pestle. Keep heating and stirring to remove moisture, then press hard to squeeze out the oil. You all work on mashing it into a paste, and leave the last squeezing step to me when the time comes, as that requires a lot of strength."

"Got it!" Lin Qianqian jotted notes in her little notebook, and immediately got busy with her friends.

Lu Zhe started making sodium hydroxide through the electrolysis of salt water!

The process was similar to lab procedures, but Lu Zhe set up the operation site at the bamboo door!

Because the electrolysis would produce hydrogen and chlorine gases, with hydrogen being flammable while chlorine was not only toxic, but could also react with the produced sodium hydroxide to generate sodium hypochlorite.

Fortunately, not much was generated. It could serve as a disinfectant. Lu Zhe opened the bamboo door a crack to let air circulation quickly carry away the generated gases.

Although the final product wasn't pure sodium hydroxide, it was already sufficient to complete saponification!

After an hour, the electrolyzed solution was ready.

On Ning Shu's side, a full mortar of mashed palm fruit had been produced.

That was enough!

Lu Zhe put a rock on top and squeezed forcefully!

With his great strength, the palm paste in the mortar endured tremendous pressure, and surprisingly, a stream of red, oil-like substance was actually squeezed out.

This was unbleached palm oil!

It was also the main cooking oil used daily by Southeast Asian people.

What came next was simple. The plant and animal oils went into the steel helmet pot, simmering and stirring all the while.

Dammar resin emulsifier and fragrance were added sequentially, before finally pouring in the sodium hydroxide solution to trigger saponification.

Gradually, these oils and fats turned into a white, gelatinous paste substance, giving off a nice aroma!

This was the soap solution!

Lu Zhe split a segment of bamboo down the middle lengthwise. Laying the two halves on the ground with the inner groove facing up as molds, he poured the soap solution into them.

"After ten-something hours, the soap will harden, but it still can't be used at that point, because the saponification reaction is very lengthy. The sodium hydroxide hasn't fully reacted yet! For non-industrial methods, it takes about a month. Industrial methods need even longer."

Jiang Yao said, "No worries, we can use pancreatin for now. Once that's used up, the soap should be nicely ready for transition!"

It took them over half a day to make the soap.

After a busy half-day, it was already nighttime.

Jiang Yao had crushed sugarcane in the mortar, extracting a bottle of sugarcane juice. Shen Bing had also prepared the snake, skinning it and laying the meat on banana leaves.

By this time, the wind outside the cave had grown even stronger. The bamboo door rattled noisily from the gusts. Lu Zhe hurriedly brought all the pork inside and wedged stones against the door.

For dinner, Lu Zhe boiled the pork belly and snake meat together, seasoning it with salt and chili peppers for a nice hot pot.

Eating their fill and having their thirst quenched, they continued to sleep.

And so they peacefully made it through the 26th day stranded on the deserted island!