Distilled water undergoes a purification process called distillation, where water is boiled into vapor and then condensed back into a liquid, leaving most impurities, minerals, and contaminants behind. This process effectively removes 99.9% of contaminants, including bacteria, viruses, heavy metals, and minerals. Distilled water can be safely boiled for various purposes.
The Process of Boiling Distilled Water
When distilled water is heated to its boiling point, typically 100°C (212°F) at sea level, the high temperature sterilizes the water. This process effectively kills any remaining bacteria, viruses, and other microorganisms that might have been introduced after distillation. Boiling for at least one minute is sufficient to eliminate most pathogenic microorganisms.
Boiling distilled water does not change its mineral content, as these were already removed during distillation. It also does not remove all dissolved gases, though many, like oxygen, are released as the water heats up, which can affect its taste. While tap water may have a slightly higher boiling point due to dissolved minerals, the difference is negligible. Therefore, boiling distilled water does not make it “more distilled” or alter its mineral-free purity.
Practical Applications and Considerations
Boiling distilled water serves several applications, often related to maintaining its purity and ensuring sterility. One common use is for sterilizing medical equipment to prevent contamination and infections. Similarly, it is frequently recommended for preparing baby bottles and infant formula, as boiling helps eliminate any potential bacteria that could be harmful to infants.
The purity of distilled water also makes it ideal for devices such as humidifiers and Continuous Positive Airway Pressure (CPAP) machines. Using distilled water in these machines prevents the accumulation of mineral deposits, which can occur with tap water and affect machine performance or lead to buildup. While boiling distilled water for these uses doesn’t change its mineral-free state, it addresses accidental contamination and ensures microbiological purity for sensitive applications.
In laboratory settings, boiled distilled water is often required for chemical processes where highly pure and sterile water is essential to prevent interference from impurities. Some individuals also prefer the taste of boiled, then cooled, distilled water for beverages, finding it to have a cleaner flavor due to the removal of dissolved gases. Since distilled water is already free of minerals, boiling it does not reintroduce beneficial electrolytes.