Why is 70% alcohol solution a much better disinfectant than a 90% alcohol concentration? Wouldn’t a higher concentration mean better?

Question

Why is 70% alcohol solution a much better disinfectant than a 90% alcohol concentration? Wouldn’t a higher concentration mean better?

In: 5202

Answer 1

90 and above % alcohol causes the outer membranes of the bacteria to shut down and coagulate forming a protective barrier. The outer proteins in viruses are not soluble in pure alcohol so they remain protective, in 70% alcohol they are disrupted and more likely to open up and let the virus break apart.