Is it good to drink boiled water that has cooled down? Is it true that drinking boiled water overnight can cause cancer? How long is the shelf life of boiled water?

We can drink boiled water that has cooled down normally if stored properly.

During the process of boiling water, the temperature will kill many microorganisms that are harmful to humans.

Most of our country's area has an average altitude of 5 to 20 meters above sea level, the mountains are higher but the water still boils at 100°C when boiled, so when the water boils and continues to boil for another 1-2 minutes, the water is safe.

Proper storage means storing cooled water in sterilized containers/bottles, avoiding opening them multiple times and placing them in places where the room temperature does not exceed 21°C. It can be stored for up to 6 months under the above conditions, but drinking water is best used within 2 days (48 hours). When it runs out, boil another clean water and discard the remaining cooled boiled water. Cooled boiled water has no effect when used to rinse dishes.

In hot summer weather conditions, the temperature is often above 21°C, plus improper storage, various microorganisms will continue to penetrate the cooled boiled water and multiply in the water. The longer the exposure time in the air, the more microorganisms there are, the worse the water quality, and the greater the harm to the human body.

Boiled water left for too long becomes slimy and must be discarded due to excessive growth of bacteria and fungi.
In addition, tea brewed overnight should not be drunk.

Water consumed daily includes boiled water, bottled mineral water, and purified water. Of these, boiled water or mineral water contains minerals, while purified water does not contain microorganisms and other minerals.

For example, white bubbles appear on the sides of a pot of boiling water, this is due to the presence of minerals.
Therefore, according to the composition, boiled water is also mineral water. Although the minerals in water are extremely small and do not have the effect of supplementing missing minerals, it is also an essential source of nutrition for humans.

Source: https://nhandan.vn/uong-nuoc-dun-soi-de-nguoi-co-tot-khong-post832268.html