Wasteland Survivalist: A Scientific Guide to Post-Apocalyptic Survival

Once his protein sources were relatively stable, Gulang stopped his time-consuming and unpredictable sea fishing and turned his attention to exploring the island's interior.

He hopes to find a wider variety of foods, especially vitamin-rich berries or edible wild vegetables.

However, the jungle exploration did not go smoothly.

Xizhai Island has lush vegetation, but there are not many wild plants that are clearly safe to eat.

He spent several days carefully traversing the dense forest.

After a careful search, only a few wild onions and dandelions were found.

The former can be used for seasoning, while the latter can be added to soup.

Unfortunately, the quantities are too small to be a stable source of vegetables.

After yet another fruitless search, he emerged somewhat discouraged from the dense forest, intending to take a detour westward back to camp.

Looks like I'll have to take vitamin pills again when I get home today.

As he walked down a relatively open rocky slope, a south-facing rocky cliff caught his eye.

A lush patch of cacti grows tenaciously in the cracks of rocks and in the dry soil.

What's even more striking is that many of the flat, fleshy stem segments have brightly colored, round fruits growing at their tips.

"Cactus fruit!" Gu Lang was overjoyed and ran over.

He put on work gloves and chose a relatively easy spot to climb.

Carefully avoiding the large thorns on the stem nodes, use a knife to cut off a dozen or so of the most purple and ripest-looking fruits.

The surface of the cactus fruit has many tiny hairs, making it look a bit prickly.

So he picked one up and gently rolled it on the stone wall, then rinsed it with water.

The knife cuts open the outer skin, revealing deep red, juicy flesh inside.

Gu Lang didn't rush to bite into it. Instead, he carefully used a knife to cut open the flesh and picked out the hidden barbs.

Then I peeled off the outer skin and tasted it.

The sweet and slightly sour juice bursts in your mouth instantly, accompanied by a unique aroma, instantly washing away the monotony in your mouth.

The flesh is sweet and juicy, with a flavor profile reminiscent of dragon fruit, melon, and strawberry.

This is not surprising, as prickly pear and dragon fruit are relatives of the cactus family.

The former has a smaller output and is more complicated to handle, so it is less accepted by the market than the latter, which has a more mature supply chain.

However, the flavor of prickly pear fruit is richer and sweeter, and its aroma is more prominent.

As for nutritional components, prickly pear fruit can be considered a "superfruit".

It is rich in vitamin C, antioxidants, dietary fiber, minerals, and some B vitamins.

For Gulang, which has long lacked fresh fruits and vegetables, this is a godsend.

He happily ate three fruits and put the rest into his backpack.

Looking at the large expanse of cacti laden with fruit in front of him, Gu Lang smiled contentedly.

Taro provides carbohydrates, seafood provides protein and fat, and cactus fruit provides vitamins and minerals.

While it's not quite perfectly balanced, basic survival needs have been met on the island.

The bounty bestowed upon Xizhai Island was far more generous than he had anticipated.

As we entered mid-October and temperatures dropped, Gulang began making preparations for winter.

He repaired an old fishing net and began casting it from the shore to catch fish according to the tide times.

When the tide rises, some schools of deep-sea fish will come to shallow waters with the tide, which is a good time to fish.

The fish that were caught were all pickled by Gulang to prepare for possible periods of food shortage.

Taro stems were also made into pickles and soaked in plastic buckets.

As a natural preservative, salt consumption has increased dramatically.

He had a limited quantity of refined non-iodized salt, which, due to its high purity, was also an important chemical raw material in his possession.

So Gu Lang took advantage of this opportunity to wander on the deserted island and began to make his own edible salt.

It is common knowledge that seawater can be boiled to produce salt.

However, the salt obtained by directly evaporating seawater contains a large number of harmful impurities.

The main components are chlorides and sulfates of magnesium, calcium, and potassium, especially magnesium ions. Excessive magnesium ion content can lead to a bitter taste.

Excessive intake can also cause health problems such as diarrhea.

It's not actually difficult to purify sea salt to an edible level.

You don't even need any instruments; theoretically, you can purify sea salt as long as you have a container.

Based on the materials at hand, he decided to use a relatively simple purification method assisted by wood ash.

The first step is to make a simple filter device.

He found a plastic bucket, cut off the bottom, and then laid down the base filter material.

From top to bottom, they are cleaned pebbles, washed and dried fine sand, and crushed hardwood charcoal powder.

They also cut an old T-shirt in half and used it as filter fabric between each layer of material.

The second step is to prepare seawater.

He went to a rocky area far from the beach with relatively clear water, filled several buckets with seawater, and let them sit for two hours to allow the sediment to settle.

Slowly pour the settled upper layer of seawater into the filter to collect the filtered, clear seawater.

The third step is to prepare saturated brine.

Originally, this step could have been done by sun evaporation, but due to the impact of nuclear war, the sunlight intensity was insufficient and the evaporation rate was too slow.

Therefore, Gu Lang still chose to heat it with fire to evaporate most of the moisture.

When white salt crystals begin to appear at the edge of the stainless steel basin, it indicates that the solution is close to being saturated with salt water.

At this point, you can slowly add wood ash.

Wood ash is a versatile material; when combined with oils, it can be used to make soap.

From the moment he landed on the island and started a fire, he had been paying attention to collecting and preserving things.

The ratio of added ash to saturated brine is approximately two tablespoons of wood ash per liter, while stirring constantly.

The carbonate ions in wood ash can react with calcium and magnesium ions to form calcium carbonate, magnesium carbonate, and other substances that are insoluble in water.

The large amount of sediment made the brine extremely cloudy.

Gu Lang let the mixture stand for three hours to allow the sediment to settle completely.

Then carefully pour out the clear liquid from the top layer and filter it through multiple layers of T-shirt fabric.

What you get at this point is a relatively pure saturated salt solution, but some harmful impurities still remain.

The fourth step is crystallization and purification.

This is the most crucial step, utilizing the principle that the solubility of sodium chloride and impurities changes differently with temperature.

The solubility of sodium chloride does not change significantly with increasing temperature.

The solubility of impurities such as magnesium chloride and magnesium sulfate increases significantly with increasing temperature.

Gu Lang divided the treated saturated brine into two parts, taking out one-tenth for later use, and boiling the remaining nine-tenths directly until dry.

Scoop out the coarse salt that has been extracted after boiling and pour it all into the reserved saturated brine.

At this point, the total amount of salt in the mixture is already supersaturated.

Continue heating the mixture. As the temperature rises, more impurities dissolve into the water due to their increased solubility.

Sodium chloride, on the other hand, has a very large total amount and its solubility changes little with temperature.

At high temperatures, sodium chloride begins to precipitate out in large quantities.

Gu Lang kept the mixture heated and stirred to fully dissolve the impurities.

While the solution is still at a high temperature, quickly pour off the upper layer of brine.

The white powder that remains is the salt crystals that have been redeposited at high temperatures and are of higher purity.

He continued to rinse quickly with a small amount of warm, fresh water and immediately poured the water away.

This can dissolve the small amount of impurity solution adhering to the crystal surface, at the cost of losing some salt.

Spread the obtained wet salt on a clean cloth and dry it thoroughly using the residual heat of the campfire.

The final product is dried, edible refined salt.