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Comment by cwkoss | Hacker News Reader

Does this bitterant leave a residue when the alcohol evaporates? That seems like one benefit of methanol vs bitterant: all of the alcohol can still evaporate without depositing bitterant as a side effect.

Are there bitterants that evaporate similarly to alcohol but are not toxic?

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The bitterent used is so powerful, the concentration is like 0.01 ppm. So unless you are in a clean room, there will be more dust from air which deposits.

https://en.wikipedia.org/wiki/Denatonium

Try cleaning glasses with it - leaves nasty stains.

Here in Germany they add Butanone, which evaporates at very similar temperatures as ethanol so it’s very difficult to purify the ethanol even with a lab setup.

We use isopropyl alcohol, which is not denatured, whenever high purity is required.

Or in a pinch, 99% grain alcohol.

Source: some friends make drinks with grain alcohol, and then don't want it any more after they make those drinks (gee, I wonder why?). Provides an essentially endless supply of alcohol for cleaning purposes for me.

If you're using alcohol for cleaning 70% concentrations are better as they actually kill and lyse pathogens at that concentration, while 99% will just desiccate them, allowing for reactivation when in a moist environment.

My hands, from working with NF/USP Isopropyl alcohol tend to disagree. It desiccates, defats, and generally kills everything in sight.

Of course alcohol is a powerful solvent at any concentration, but there are definitely studies[1] that demonstrate 70% being a bit more effective at disinfecting.

[1]: https://www.webmd.com/first-aid/ss/rubbing-alcohol-uses

That's always been the rule of thumb that I learned growing up too. My dad kept 90% or stronger concentrations for cleaning electrical contacts and other industrial uses, and 70% for first aid and sanitizing, because that's what each was made for.

Well, today I learned. Thanks.

You probably mean 95% grain alcohol if you’re making cost-effective non-toxic drinks with it.

Yes, just checked and my current bottle is actually 190 proof, good call. But I swear I've gotten a bottle covered in Russian text that claimed 198 proof before. Not sure how reliable that is, to be fair.

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