91% Isopropyl Alcohol: Scale Down the WHO Hand Sanitizer Formula

The previous video showed how to scale down the WHO hand sanitizer formula to make any amount using of pure or 99% isopropyl alcohol. (Scaling Math: WHO Hand Sanitizer Form...)

Alcohol is sold in different strengths. For the weaker solutions, you need to add more milliliters to get the same amount of alcohol.

If you are using 91% alcohol, divide the amount of pure alcohol needed by .91. For example, to make 320 ml of hand sanitizer, you need 240 ml pure alcohol, or 240/.91 = 264 ml of 90% alcohol.

If you are using 70% alcohol, you to REMOVE water from the solution to get 75% alcohol in the final hand sanitizer. The next video shows you what to do in that case.

Modify the formula to use 70% isopropyl alcohol
70% Isopropyl Alcohol: Scale Down the...

Modify the formula to used ethanol instead of isopropyl alcohol
Ethanol 180 & 140 Proof: Scale Down t...