I’m always learning. And that’s a good thing even when it feels mildly annoying.
Like falling down and picking yourself up again.
Like learning that my original homemade hand sanitizer recipe might not have been up to proper germ killing standards.
My original homemade hand sanitizer recipe used a 50/50 ratio of 70% isopropyl alcohol to aloe vera gel. I used this hand sanitizer all last winter, was not sick a day, and liked it lots. BUT – then I received the following comment:
I think it is extremely important to inform you that your sanitizer DOES NOT contain the required alcohol percentage to kill germs. You are using 70% alcohol and mixing it 50/50 with aloe gel. This, in theory says that your alcohol percentage is approximately 35%. This will NOT kill germs. You NEED 65-70% alcohol to make your sanitizer effective. If you are making this recipe, you will need to use 99%to 95% alcohol and less aloe/glycerin/other gels. With your recipe, all you get is a bottle of false security.
OK, that called for some investigation.
Q: Is this true? Do you need more than 50% alcohol?
A: Looks like a Yes. The current scientific research states that the alcohol concentration must be over 60% in order to kill microbes.
Q: So are the store bought varieties of hand sanitizer at this percentage of alcohol?
A: The Purell FAQ page lists their active ingredient as 62% ethyl alcohol.
Q: What’s Ethyl alcohol?
A: Pure grain alcohol. Ethanol. Like I think you can run your car on that stuff.
Q: What’s the difference between ethyl alcohol and isopropyl alcohol?
A: Not much. Basically they have a slightly different chemical structure. There’s a shorter carbon chain on the ethyl alcohol.
Q: So is one better than the other?
A: Lots of scientific gobbledy gook. Can’t make sense of it all. Head swimming. Thinking about getting a snack.
My investigation did take me far enough that I decided my original recipe needed some tweaking. Two things had to happen.
#1 – I needed to use the 99% Isopropyl Alcohol (instead of the 70%) to keep the alcohol percentage high enough; and
#2 – I needed to use 2 parts alcohol to 1 part aloe gel (instead of equal parts). This would result in an approximate 66% alcohol to 33% gel.
So I made a little test batch – AND – the disappointing thing is you get a much thinner mixture.
It didn’t stir together as nicely as my original mixture either. It really needed a good shaking once I had it in my pump bottle before it appeared to be mixed together well. It still rubbed into my hands nicely, however, and the alcohol smell fades away quickly.
The updated recipe measurements below should meet the prevailing wisdom on the needed strength of a hand sanitizer and is still quick and easy to whip up at home as needed.
HOMEMADE HAND SANITIZER
1/4 cup Aloe Vera Gel
1/2 cup 99% Isopropyl Alcohol
Place the aloe vera gel in a bowl. Add the alcohol slowly, stirring as you go to mix it into the aloe gel. Transfer the mixture to a small pump bottle and shake well.
* Note: You should be able to find the 99% Isopropyl Alcohol in drug stores in the same location as the 70% variety.