What's the Difference Between Ethyl and Isopropyl Alcohol?

These two alcohols can both be used to make hand sanitizer, but only ethyl alcohol is drinkable. Learn how ethanol and isopropanol differ in this episode of BrainStuff.

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Episode Transcript

Speaker 1 (00:01):
Welcome to brain Stuff, a production of iHeart Radio. Hey
brain Stuff, Lauren Bogelbaum. Here, Washing our hands with soap
and water is the number one way to kill and
remove bacteria and viruses. But we're not always just hanging
around a sink when we need one. That's why a
little bottle of hand sanitizer comes in very well. Handy,

(00:24):
so portable, so easy, pretty effective. Of course, in the
early days of the novel coronavirus pandemic, the United States
ran into a shortage of hand sanitizer, but many distilleries
came to the rescue. They had lots of alcohol on
hand or the means to order it, so they pivoted
to manufacturing bottles of hand sanitizer to help fill local

(00:45):
gaps and supply. But is the alcohol in whiskey or
vodka the same as alcohol in regular store bought hand sanitizer.
The short answer is not exactly, but it's fine to
use either as a disinfectant. Here's why. The most common
hand sanitizers use isopropyl alcohol, sometimes called isopropanol or rubbing alcohol.

(01:07):
You might have a bottle of it under your bathroom sink,
and you cannot drink this stuff. It will make you
sick and it will not make you drunk. The alcohol
that we humans do drink is ethyl alcohol, sometimes called
ethanol or grain alcohol. You might have a bottle of
this in your liquor cabinet or a diluted version in
your fridge. Since it's the kind of alcohol we talk

(01:29):
about when we talk about any alcoholic beverage, be it beer, wine, liquor,
or otherwise. Different human bodies react differently to it, but
small amounts generally won't make you sick, and it can
definitely get you drunk. Now, ethyl and isopropyl alcohols have
sort of similar molecular structures. Both consist as all compounds

(01:49):
that we call alcohols consist of at least one molecule
of oxygen plus hydrogen bound to an atom of carbon,
but beyond that, their chemical variations are enough to make
one drinkable and one dangerous to ingest. But when it
comes to hand sanitizer, they work the same way. Research
into exactly how it works is still ongoing, but they

(02:11):
both seem to muck around with the structure of proteins
and lipids and viruses and bacteria. They can dissolve membranes
and disrupt inner function, which kills those germs. For hand sanitizer,
the US Centers for Disease Control and Prevention recommends a
solution of between sixty five to alcohol, using either ethyl
or isopropyl alcohol to get the job done. But if

(02:35):
a little alcohol is good at killing germs, isn't more better?
But why stop it's sixty seventy percent alcohol when you
can go all the way to one well? Because it
turns out that one alcohol is actually less effective at
dealing death to those dastardly diseases. When the alcohol begins
to do its work on bacteria, for instance, the injury

(02:56):
to the cell's outer wall can cause the bacteria to
form a protect of shell around itself. That's bad, the
viruses don't form those protective shells. But higher concentrations of
alcohol also evaporate very quickly, maybe before it could have
the chance to penetrate the viruses outer walls. That's also bad.
Adding ingredients that evaporate more slowly than alcohol means the

(03:19):
alcohol in the solution lingers longer on your hands. So
adding stuff like water, hydrogen peroxide, glycerol, and aloe can
make the solution even more effective. That evaporation factors into
our comfort too. Ethanol is more dehydrating, and we can
feel that when we use it on our skin. It
can make our skin feel tight and dry. A suppropyl

(03:42):
alcohol evaporates more quickly, but it doesn't dry out our
hands so badly. That's same super quick evaporation rate is
why we use rubbing alcohol to clean electronics. By the way,
I suppropyl alcohol got the more common name rubbing alcohol
in the nineteen twenties because it was used in liquids
or lotions that were rubbed into the skin for health
and healing. This was also the prohibition era, so this

(04:05):
good alcohol needed to be set apart from the bad
ethel alcohol that was banned at the time thanks to
the Eighteenth Amendment. Bravo to those distilleries who have been
turning it back into a health product in these are
COVID times. Today's episode was written by Kristen hall Geisler

(04:25):
and produced by Tyler Klang. For more on this and
lots of other high proof topics, visit how stuff works
dot com. Brain Stuff is a production of I heart Radio.
For more podcasts my heart Radio, visit the iHeart Radio app.
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