Pa loves his coffee.

I never thought about that.

When we lived in Kenya, it was fun to stay at a rural home with coffee growing outside our bedroom window.

Another common essential was whiskey. It was about the only effective medicine to be had (anesthetic/antiseptic).

I recall reading somewhere that coffee began to take hold in the US following the tax issues that culminated in the Boston Tea Party. If coffee did get traction I could see how by 1870 it was considered a staple. I also recall seeing lots of coffee pots in Civil War camp scene paintings. That would have been just a few years before the books were based.

According to this site on Prairie foods, coffee was common by the 1850’s: http://www.foodtimeline.org/foodpioneer.html There’s an excerpt of a book discussing coffee on the Oregon Trail: http://www.foodtimeline.org/foodbeverages.html and the following advice is given:

“Although Peter Burnett advised his family, “If you are heavily loaded let the quantity of sugar and coffee be small, as milk is preferable and does not have to be hauled,” his counsel was the exception. Most emigrants took the advice of Anna Maria King: “Fetch what coffee, sugar and such things you like, if you should be sick you need them.”

and right below there’s this Civil war excerpt:

“Finally there was coffee. Soldiers could go for days without food, if only they had their coffee. In the Confederacy it became as highly prized as shoes, and commanded outrageous prices in times of scarcity. Substitutes were tried using chicory or parched corn, but nothing approaced the real article. As a result, coffee was the item most often requested when Rebs informally met Yanks between the lines for illict trading. Virginia tobacco being the commodity exchanged. In the North, by contrast, there was rarely any shortage of coffee beans, and many regiments were actually issued special rifles, one per 100-man company, with a coffee grinder built into the butt stock. The best coffee was slow roasted over a low fire, “until of a chestnut brown color and not burnt, as is so commonly done.” It was to be boiled briskly for two minutes, then take from the fire at once, a little cold water thrown in, then the boiler’s contents poured through a piece of flannel after it had settled for five minuutes.”
—Civil War Cookbook, William C. Davis [Courage Books:Philadelphia:PA] 2003 (p. 16)

I’ve always thought it funny that Cafe du Monde touts its “coffee and chicory” as chicory was simply a poor man’s way to stretch coffee.

I’ll have to send my nieces and nephews researching this. They are my rural American distributed research network. Sort of a mechanical turk of kids under 15.