The Delightful Dilemma of Embalmer's Delight

In Druvenia, shady dealings are the norm and you can count on shenanigans being afoot. But even in this den of mischief, there are some mysteries that eclipse the rest.
  One such mystery is what exactly happens behind the closed doors of the Drowned Rat Distillery, where Embalmers Delight is distilled.
 

Speculation and urban legends

As the distillery itself is closed to the public and its proprietors are not forthcoming with information, speculation about what goes into the production of Embalmer's Delight is plentiful.
  A popular tall tale that makes the rounds in Druvenia is that the distillery recycles the sewage water that runs below the building, fermenting whatever festers in that sludge and distilling the liquor from it.
  While this is a striking and even half-way plausible take on the issue, if the Drowned Rat really used fermented sewage to distill spirits, those consuming Embalmer's Delight would fall ill much more often than they actually do.
  Another version makes the claim that the employees of the distillery, who are required to live in the building are actually thrown into the fermentation vats after they become too weak to keep working. This evocative spin on the mystery is also unlikely for the same reason as the earlier version, that is to say that the liquor would be much more unfit for human consumption if it was distilled from fermented corpses.
  Finally, a lesser known version of the story, purported to have been told by an escaped employee of the distillery, claims that there is a creature of some sort that has been imprisoned in the bowels of the building, which the employees extract fluids from that are used in the fermentation process.
  This sounds like a horror story to scare children, but one cannot just discard it out of hand when it is Druvenia that is being talked about. Anything and everything is possible in the city with no rule of law.
  Whatever the truth is, it is likely to remain hidden as those in charge of the distillery are wont to keep their secrets.
 

Investigation

The Drowned Rat Distillery has come under considerable scrutiny from the Druvenian Purification Guild, who maintain that the establishment must allow inspection of its premises to ensure that their methods and ingredients do not pose a health hazard to the Druvenian public.
  So far, none of the notices left on the doors of the distillery by the guild have been reacted to in any meaningful manner.
  There is an urban legend that claims that Purifiers working behind the backs of their superiors allegedly infiltrated the distillery at an undisclosed date. The next day, the servants of the guild discovered a wooden crate adorned with a green bow containing two bottles of Embalmer's Delight next to the main entrance of the guild facilities. The purifiers in question purportedly never returned.
  This tale has been told and retold many times, with varying perpetrators for the infiltration of the distillery.