[xxxCarlxxx]

This should be a simple question...

If we add, for example only (not a real formula), let's say 1 cup of 70% alcohol to one cup of aloe, is the alcohol still 70%, or is it now 35%?

I am trying to understand if the 70% target refers just to the alcohol component or to the entire formula.

TIA

Dr Carl

[Borek]

You need it to be 70% of the final composition, so if you start with 70% you can't dilute it any further.

[xxxCarlxxx]

Thank You!

[Enthalpy]

Is aloe vera useful?

[sgojja]

you can also see WHO recommendations on wikipedia, its a solution of alcohol, glycerol with whatever ABV you would chose, then top up with water to make the final volume, however, one thing that you might want to consider at last will be molar excess volume to get the overall decrease in volume, for practical purposes.

[billnotgatez]

@sgojja
Are you assuming 90% alcohol before mixing?

@Enthalpy
I heard that aloe vera counteracts the negative effects of alcohol on the skin.

[sgojja]

you can assume anywhere between 60 and 95, if you consider very higher concentrations of alcohol, you may neglect the molar excess volume. In current scenario of COVID-19, its better to make sanitizer in higher concentration of alcohol.

[billnotgatez]

@sgojja
I have heard that the goal is to have 70% alcohol in the final solution?

In any case that was the original final solution goal of the op