When back in the village, she tells them to sell it somewhere with a bad lie excuse as to why they shouldn't try drinking it.
Interesting. I don't fully recall that.
I'll have to scrub through the editor to figure out past that. But my only other suggestions would be to pop in with all the NPCs in the village. Mistress Arianna, Jinam, and/or the Quack.
But I don't recall ever having any text mentioning it past that scene. Though that was the last area I was doing so I was more than eager to just get this pushed out lol. So maybe I over looked something.
Edit: It seems like it might just be something you "get". There's no mention of it anywhere in the village, whether Mel or Quada, or the shop NPCs. And the last mention is in the castle stage. So either it's buried somewhere as a "secret" use (mildly unlikely) or it's just meant to be a thing you collect to fill up the item gallery. This was a post-release "DLC", so I'd put my money on that maybe Acid Style threw that in and didn't have any plans for it past that?
Maybe it's involved in getting the new game+? Though I have my doubts about that.
I think it's safer to say it just doesn't have a use lol.
No one raised questions about it on his Ci-En announcement post from that point onward, so I truly can't say for certain.
Edit 2: It COULD also be addressed in a further update with some flavor text, and just not in this version of the game. (This translation version was built off a specific version. I recall someone mentioning there might be one more "bug fix/tweak" update past this version it's on. But I'd have to dig through everything in that new version to find out lol.)
Edit 3: Well. There were three updates past this lol. Most of them bug fixes and tweaks. Pretty heavy from his past Ci-En posts...
I now have to decide if I want to update this to said newest version. As it'd be a fuck ton of work lol.