As Twain said: "Then he poured for us a beverage which he called “Slum gullion,” and it is hard to think he was not inspired when he named it. It really pretended to be tea, but there was too much dish-rag, and sand, and old bacon-rind in it to deceive the intelligent traveler." Just to be sure, I looked it up: slumgullion
cheap or insubstantial stew.
1. a stew of meat, vegetables, potatoes, etc.
2. a beverage made weak or thin, as watery tea, coffee, or the like.
3. the refuse from processing whale carcasses.
1840-50, Americanism; compare Scots, Hiberno-English gullion quagmire, cesspool
from slum in US sense slime + gullion, perhaps variant of cullion testicles
So, a nice thin beverage made from slimy whale testicles, which by the time they got to Kansas would likely have been rather aromatic as well as slimy.
Still, while food was extra, just like on today's airlines, the stage trip cost only $150...or more than $3500 in today's money.