Lately I haven't been answering many questions because it kind of spoils the fun, but this time I'll answer a thing or two.
Bottles of healing wine are spontaneously created at a somewhat regular interval, but no one knows where they'll show up next. That's unpredictable. Because of this, Asterion used to stash them whenever possible. The bottles stopped appearing during the time Asterion was alone in the hotel. The bottles cannot be commanded to appear, not even by the master. In old times, when Asterion was being tortured, they used to appear much more frequently.
It is possible to make the healing wine, but only the Argoi know how. Not even Asterion knows it. Originally we planned to show how it's done during the Ruthless Route but we ended up cutting it.
The current Argos, despite knowing how to make the wine, does not understand the logic behind it. He does not know why it works.
If Asterion drank the healing wine while he's not injured he'd feel great. He used to do it every now and then in special occasions. There would be no negative consequences to it. He becomes inebriated by it but it leaves no hangover.
Asterion does not allow anyone to drink the healing wine. It does not heal anyone but him and, in fact, can make others terribly, violently sick.