To disinfect tools effectively, ethyl alcohol must contain a minimum percentage of what?

Ethyl alcohol is a commonly used disinfectant in esthetics and medical settings due to its effectiveness in killing a wide range of microorganisms. To ensure proper disinfection, ethyl alcohol must reach a concentration of at least 70%. This concentration is crucial because it provides a sufficient amount of moisture which allows the alcohol to penetrate the cell walls of bacteria and viruses more effectively.

At 70%, ethyl alcohol is more effective at denaturing proteins and dissolving lipids, leading to better microbial kill rates. Higher concentrations, such as 90% or 100%, evaporate too quickly to be effective as disinfectants. They may not allow adequate contact time on surfaces to achieve disinfection. Therefore, for effective disinfection and ensuring microbial safety, the minimum percentage of ethyl alcohol required is indeed 70%.