Granted, when I inspected closely the bottle actually said Francis Hartridge's Celebrated Root Beer, but my initial reaction seemed appropriate, and I thoroughly recommend it.
As I do this book, in fact. It's a sequel to Fly by Night, Frances' debut novel. Although it says it is set about three months after the previous book, it is several years since I have read that and it certainly isn't a prerequisite (though it's worth it for its own sake). To me, this book seems more timeless in its setting, more detached and purely fictional (Fly by Night has enough historical references to place it, although it is in a fictional land). The story begins with Eponymous Clent in a debtors' prison, and Mosca Mye attempting to earn money for his release by reading - reading anything, to a largely illiterate population. Oh, and there's a goose, Saracen, to which Mosca is fiercely attached.
Mosca earns the money to buy Clent's release, but in the process discovers a plot, which she determines will have to be stopped. This involves the trio visiting the town of Toll, which turns out to be divided, into the overtly respectable Toll-by-Day and the undesirable Toll-by-Night. In their attempts to foil the plot, they will learn of the devious ways of many inhabitants in both parts, as well as some of the good ones. The plot twists, and twists, and then twists some more. It's clever stuff and well thought through.