At noon, everyone had breakfast.

Liu Yuhan led Liu Shinan, Huo Dong and Liu Hong, carrying tools and backpacks, and went to the mountain to find a place to collect saltpeter.

When we got there, we used pickaxes to break up the saltpeter, which was still quite hard. The three men each carried about 50 kilograms and returned.

After returning to the small courtyard, all that was left was for Liu Yuhan to carry out the task on behalf of his master.

Making ice from saltpeter is not very difficult.

First dissolve the saltpeter.

Liu Yuhan took out a large wooden barrel, put the saltpeter into the barrel, added enough water to completely dissolve the saltpeter, and covered the barrel with a wooden lid to prevent the water from evaporating.

This process may take some time because the saltpeter needs to be fully mixed with the water. Liu Yuhan stirs it with a shovel so that the saltpeter will dissolve faster.

All that remains is to cool the solution.

Move the barrel to a cooler place. The lower the temperature, the easier it is to cool. As the temperature drops, the water in the solution will gradually freeze.

This process takes about an hour. Saltpeter dissolved in water will absorb a large amount of heat, causing the water to cool to the freezing point and freeze.

Since then, there has been a method of making ice in summer. After saltpeter is dissolved in water, it can be extracted and reused by cooling crystallization or evaporation crystallization.

Huo Dong and his team observed the solution in the barrel closely and found that it was getting colder and colder as time went by. When the solution completely cooled and froze, everyone was stunned!

Wow, this really makes ice! This is incredible!

If ice could be made, it would be a huge help to the scorching south, especially to their coastal cities. Just from keeping food fresh during shipping and providing relief from the summer heat, the profits would be immeasurable.

They usually store food in refrigeration methods: ice cellars, ice jars, and wells.

The most direct way to preserve food is to use low temperature, which can inhibit the growth of bacteria and the spoilage of food.

Therefore, the ancients came up with various ways to use natural ice, snow or water sources to create a low-temperature environment. They would build ice cellars according to the environment to store food.

Of course, natural ice and snow cannot be found everywhere. In some places with dry climate or scarce water resources, the ancients could only use wells to preserve food.

In the summer, put food in a wooden barrel, then lower the barrel into the well, let half of the barrel sink into the water, and then cover the well.

Because the well water is a certain depth from the ground and the temperature is relatively low, the food can be preserved for a period of time.

Modern people still use this method. Watermelon chilled with well water tastes very good.

Methods of storing food: sun drying, smoking, pickling, and soaking.

In addition to using low temperatures to preserve food, the ancients also invented another method, which is the drying method.

The principle of drying is to remove moisture from food and reduce its activity, thereby inhibiting bacterial growth and food spoilage. There are many drying methods, such as sun drying, smoking, pickling, and soaking.

Sun drying is the simplest and most common drying method. Ancient people would place harvested grains, vegetables, and fruits in the sun to dry them, causing them to lose moisture and preserve them for a long time.

The raisins, mushrooms, and wolfberries we often eat are all sun-dried products. Sun-drying not only extends the shelf life of food, but also increases its aroma and nutrition.

Pickling is a method of preserving food using salt or other seasonings.

The ancients mixed food with salt or other seasonings to cause it to lose moisture. The food was penetrated by the chemicals in the salt or other seasonings, thus achieving the effect of preservation and flavor enhancement.

The pickles, kimchi, and braised meat we often eat are all pickled products. Pickling not only preserves food, but also adds a variety of flavors to the food, such as sour, sweet, bitter, and spicy.

Of course there is another method of isolation: sealing and canning.

In addition to using low temperature and drying to preserve food, the ancients also invented a third method, which is isolation.

The principle of the isolation method is to preserve food by isolating it from external factors such as air and bacteria.

The ancients placed food in sealed containers, such as pottery jars, wooden barrels, bamboo tubes, etc., to isolate them from air and bacteria, thereby achieving the effect of preservation.

The bacon, preserved fruits, fermented bean curd, etc. that we often eat now are the products of the isolation method. The isolation method can not only preserve food, but also increase the aroma and richness of the food.

An advanced version of the quarantine method is canning. Canning is a method of preserving food using high-temperature sterilization and vacuum sealing. First invented by the French in the early 19th century, canning later gained widespread military and civilian applications. Cans can preserve a variety of foods, including meat, fruits, and vegetables.

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Although the saltpeter ice making method requires some time and patience, its results are very good.

The ice cubes made in this way not only have a good cooling effect, but also do not contain any chemical additives and are very healthy.

Although it is not recommended to drink saltpeter ice directly, it is actually edible. Pay attention to the hygiene of the saltpeter and keep the added water clean. During the freezing process, some impurities and microorganisms will be eliminated during the formation of ice, making the quality of the ice relatively good and easier to drink.

Of course, no water is better than boiled water.

Everyone was marveling at the magic of ice making.

Liu Hong and the others also picked up wooden buckets and began making ice. The ice was useful, and they used it to freeze the seafood and meat they had hunted.

Huo Dong has had a strong learning ability since he was young, and he knew how to operate it at a glance.

The Huo family has their own merchant fleet, which often transports goods from the south to the capital. If they had a way to make ice, they could do more.

My dear, there is more to this chapter. Please click on the next page to continue reading. It will be even more exciting later!