Oshizu, build a small, doorless room, or add a stairless basement. Keep your ambrosia and/or ambrosia ingredients there. Only the Watchett will be able to access it and give it to the appropriate Sim.
Actually, when I was googling something else recently, I read about a Nov 25 2014 patch which prevents sims from autonomously eating ambrosia.
http://forums.thesims.com/en_US/discussion/801327/november-25-patch-notes [it's the 3rd bullet under "Tuning/Graphics"]
@Joria Thank you for your advice. I do have a doorless room on the inaccessible roof, but several sim weeks ago I started moving ambrosia to the immortals' personal inventories when they received their first notice.
However, you and Marian are both right; I just need to be more mindful and less lazy. The fuller the household, the harder to keep track of everyone...
Since MarianT's response, I've also moved all reward potions out of the sims' inventories and fridge to that doorless room, too, just to be safe.
I vaguely remember IDC storytellers remarking that ghosts were eating their ambrosia museum items (or was that for Sims 3?).
So, I'm confused about how to most efficiently store ambrosia and I admit to sometimes being an absent-minded Watcher.
I haven't had any ambrosia disappear from personal inventory or fridge yet, though I need to watch a sim cooking ambrosia because they sometimes wander off to do something else.
