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Comment by pard68 | Hacker News Reader

I am impressed. I was under the impression that this stuff works because alcohol kills basically everything.

Looks like we need to start washing with Everclear now.

That's what I thought as well. When I took a biology class in college we asked why hand sanitizer that kills 99.9 percent of germs is fine, but excessive use of antibiotics breeds super germs. The professor told us that it just destroys it at a molecular level, so there's nothing to resist, it'd be like trying to develop a resistance to being torn apart by a black hole.

That's my understanding as well. Bacteria cannot survive in alcohol because the lipid structure in their cell membranes are disrupted and their proteins become denatured

It's known that some bacteria can survive just fine in moderate concentrations (the paper points out lactic acid bacteria in sake, surviving at more than 18%) by means of membrane transporters.

The authors suggest that insufficient concentrations could allow tolerant bacteria to survive.

> As alcohol tolerance increases, we hypothesize that there will be skin surfaces in contact with alcohol-based hand rubs or inanimate surfaces in contact with other alcohol-based cleaning agents that do not receive the maximum biocide concentration or contact time required for effective bacterial killing.

Yes, it looks like 70% was required for the resistant bacteria

70 percent is usually said to be the best concentration as a trade off from lethality to the microorganisms to the time it takes to evaporate.

Reminded me of this comic.

http://ubertoolcomic.com/?comic=no-138

> Looks like we need to start washing with Everclear now.

It's actually backwards from that. Adding some water to alcohol kills more bacteria than pure alcohol.

See here: https://blog.gotopac.com/2017/05/15/why-is-70-isopropyl-alco...

CA-Legal "Everclear" is actually perfect for this, at just 75.5% ABV.

Ditto VA Everclear. But... if you make a run to WV it's like 95%.

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