No idea. I'm wondering if the glycerine in commercial sanitizer has anything to do with it?
But I did happen to make a batch of hand sanitizer, just yesterday.
Aloe grows like a sumbitch here in AZ and I have a couple of plants in the backyard. Took some aloe, fileted it to get the goo out and blended it up to chop up any plant matter, added 99% iso alcohol at a 3 parts alcohol to 1 part aloe ratio to wind up around 75% alcohol. Poured the thinned aloe/iso solution through a strainer to remove the chopped up plant cellular matter, and put the resulting liquid in bottles.
Supposed to have a shelf life of several months before the aloe goes bad. Runnier since there's no glycerine. But sterilizes, and deals with the alcohol drying your hands by also providing aloe.