When working with ethanol standards, the way we store them matters a lot. Big containers may seem more economical, but actually, the smaller, individually sealed tubes have some big benefits.
The big issue with a large container is that after it has been opened, ethanol can vanish into thin air - literally. This evaporation changes the % and therefore the efficacy, rendering a standard with a long in the future expiration date ineffective.
Individual, smaller, sealed containers don't have this problem. Each container is like opening a brand-new, untouched batch every time, which means your instruments and your values stay spot-on.
So, while big containers may seem handy at first, the little guys do a better job in keeping your ethanol up to the mark. It's something to think about next time you're dealing with ethanol standards!