Boiled Water: Benefits and Risks from a Chemistry, Microbiology, and Physiology Perspective Introduction: Thermal treatment as the oldest method of purification Boiling water is one of the oldest technological methods used by humanity for its disinfection. From a scientific point of view, it is a physicochemical process that leads to profound changes in the structure and composition of water. Its impact is ambiguous: it solves a number of critical problems, but at the same time, it creates new ones. An assessment of benefits and risks requires analysis at three levels: microbiological, chemical, and biological (impact on the body). 1. Benefits: Destruction of pathogens and reduction of risks The main and undeniable benefit of boiling is its antimicrobial effect. Denaturation of proteins. High temperature (100°C at normal pressure) causes irreversible denaturation (coagulation) of protein structures in the overwhelming majority of vegetative forms of microorganisms: bacteria (including Escherichia coli, Salmonella, Legionella, cholera vibrio), viruses (enteroviruses, rotaviruses, hepatitis A virus), and many protozoa. This makes the water safe from an epidemiological point of view. Removal of volatile compounds. Boiling removes dissolved gases from water: chlorine (used in municipal disinfection stations) and its by-products (chloroform, trihalomethanes), as well as hydrogen sulfide. This improves the organoleptic properties of water (the smell and taste of chlorine disappear). Reduction of hardness. With prolonged boiling, part of the hardness salts (calcium and magnesium bicarbonates) precipitate out as an insoluble sediment (scale). This temporarily reduces the total hardness of the water, which may be beneficial for people with sensitive digestion or a tendency to kidney stones (although the direct link between hard water and kidney stone formation is not proven). Interesting fact: Not all microorganisms die at 100°C. Spores of some bacteria (for example, ... Read more