I've been experimenting with a grease that is used on our 737's, Aeroshell 33, I placed about a cup in a plastic container with a cover on it, left it outside from mid May to the first week of October last year, never separated, that's with being exposed to 100 F.+ for a majority of the time.
Also put it a freezer that is used to store composite repair materials, it's kept at about -5 F., after 4 weeks in the freezer, I could stick my finger into it, no noticeable thickening.
This is what I used on my alternate steering head bearing lubrication, last week.