Why is 70% ethanol preferred for aseptic techniques?

Question

Are other concentrations (say 80%) less effective,or is this just for convenient manufacturing? Is the concentration chosen only because it is less volatile than 100 percent ethanol and hence safer?

Answer 1

Ethanol is not so dangerous. You can hang around near moonshine (pure ethanol) and not get drunk. I learned a long time ago 70% ethanol is favored because it is because it takes it longer to evaporate, and therefore hangs around more on a surface, giving it more time to kill microbes. I'm not 100% sure this is the reason, but it sounds reasonable.