PART 1: Creating Baseline with isopropyl alcohol & Proof Hydrometer to make DYI hand sanitizer

In this video I am creating a baseline for a cheap proof and tralle hydrometer. I am creating a baseline to see if the calibration is in the 70% to 80% range using isopropyl alcohol.
Isopropyl has a density of 0.786 g/cm3 (20 °C), and ethanol at 0.7893 g/cm3 (20 °C). This makes isopropyl lighter so the hydrometer will sink a little more since a hydrometer for proof/tralles is weighted and calibrated for ethanol alcohol.

The easiest way to figure this out is first check your Hydrometers again ethanol, any liquor in the house. If you can’t do this that’s ok, even the cheapest one I bought was off my 0.5 on the scale and the results are still over 70% as recommended.
W.H.O. states at 77F (25C) the isopropyl shows up on the hydrometer +2.

I confirmed this by messing 3 parts isopropyl alcohol and 1 part distilled water for a 75% isopropyl mixture.

*Note: don’t forget this next step:
Take a measurement with the hydrometer and deduct points for the temperature of the solution based on the calibration chart that came with your hydrometer.

My control of 75% isopropyl came out at 83.5 on my hydrometer, the temperature of the solution was 75 degrees Fahrenheit. According to my chart the hydrometer came with I needed to subtract 6 for the 75F solutions between 50% and 100%, this gave me 77.5 for the hydrometer reading.

So now I know 77.5 on the hydrometer is equal to 75% isopropyl alcohol at 75 degrees fahrenheit for my measurements when creating the sanitizer with isopropyl alcohol.

This is why using the W.H.O. formula they mention in the documentation that isopropyl percentage shows up higher as 77 on the hydrometer @ 25C when they compared the ethanol batch to the isopropyl batch (page 4, under quality control, step #3).
Accuracy is only as good as the testing instrument and is why I did a controlled mix of 1 part distilled water and 3 part 99%+ isopropyl mix. From this I concluded the same thing the W.H.O saw, with an additional 0.5 out of calibration for my hydrometer.
Even if someone doesn’t take this factor of density into consideration and your shooting for 75% reading in the hydrometer then the actually percentage content would be around 72% (+/- 1) and still be above the CDC and WHO 70% recommendation needed.

This way I can compensate for this when making the hand sanitizer rub using the formula from WHO (world health organization).

Mark Rober: How to see Germs Spread
   • How To See Germs Spread Experiment (Corona...  

Part 2 for making hand sanitizer:
   • PART 2: DYI Hand Sanitizer from World Heal...  

Hydrometer Purchase:
https://www.amazon.com/gp/product/B00...

Bear Hydrometer Kit with glass cylinder:
https://www.amazon.com/gp/product/B07...

CDC's Alcohol recommendations for sanitizer solutions:
https://www.cdc.gov/coronavirus/2019-...

World Health Organization Recommended Hand Rub Formulations:
https://www.who.int/gpsc/5may/Guide_t...