I can hazard a guess that it could be like that to stop masters and others keeping them for themselves by making them useless if not toxic to them
In Greek mythology ichor is poisonous to mortals as it's usually described as blood of a god, it's either intentional they added ichor to the wine as a way to stop mortals stealing the wine from its intended user or it's just bi-product of its process to making the wine. It could cross the line as it would be an insult for a mortal to even attempt to consume a divine substance.
yeah, that's what i'm saying. ichor would fit this property of the wine. the idea that it's made with asterion's blood specifically makes for a self sustaining production, the more he gets hurt, the more healing is available to him. the one blindspot i'm still unsure is why production ceased when the hotel was abandoned, there may be something else caused by other people being around to make the wine.