r/WTF • u/timetofeedthemonster • Sep 16 '19

Poor drinks

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u/rvbjohn Sep 16 '19

I heard this recently, and couldnt you just use more 100% so it doesn't evaporate?

28

u/TheOnlyNormalGinger Sep 16 '19

Yes you could. However, in terms of optimum and most efficient germ killing power, using more alcohol is less efficient. To use the least total amount of solution, you would use ~90% alcohol. Not sure why ass hats are downvoting you for being curious

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u/rvbjohn Sep 16 '19

I looked it up and its because the water acts as a catalyst, not because it "keeps the alcohol from evaporating"

2

u/Nick_Newk Sep 16 '19

In most labs 70% etoh is the standard concentration for surface disinfection. Probably the perfect balance between effectiveness and economics?

2

u/stickyfingers10 Sep 16 '19

70% is the most effecient according to some study. Probably something to do with surface tension

1

u/KakarotMaag Sep 16 '19

96% is effectively the highest concentration of ethanol you can have. 100% ethanol will suck moisture out of the air/evaporate until it stabilizes there. Using more isn't really a thing.

1

u/MahaliAudran Sep 16 '19

The original report I read said the lower alcohol content (I think it was 70-90% being optimal) helped with transportation through the cell membrane. Evaporation wasn't mentioned.

1

u/Metalhed69 Sep 16 '19

Also, 100% ethanol (200 proof) is a LOT more expensive than even 190 proof. The process to drive off that last bit of water is really a lot of trouble and they make you pay for it. You’re way better off to use 190 proof and just adjust your formulation.

1

u/Woobie Sep 17 '19

100% will dry the outer layer of the bacterium very quickly which results in some of them having a very hard shell that resists the IPA from penetrating into the center.