This books http://books.google.com/books?id=5rJsL3 ... ey&f=false
Alcohol in History: an account of intemperance in all ages, (1887) by Richard Eddy gives the following recipe for making imitation Monongahela whiskey:
40 gallons high proof corn whiskey
3 gallons tincture Guinea pepper
40 gallons water
1 quart tincture pellatory
2 ounces acetic ether
1 1/2 gallons strong tea
I think pellatory may be a reference to pellitory herb, the root of which was used. http://www.botanical.com/botanical/mgmh/p/pellit19.html
One reference to medieval sauces where it was used suggested using horseradish as a substitute. Acetic ether refers to ethyl acetate.
I suspect that the author of this recipe must have based his on some imitation rather than the authentic stuff.