Firkin is a funny word. It was not familiar to me until I stopped at Oskar Blues in Lyons, CO for lunch over the Labor Day weekend.
In the literature about the bar/restaurant/brewery, they mentioned many musicians that would be there in the coming month. The calendar of events also has listed Firkin Fridays. Many people I know would opt more for firkin Mondays, but I digress.
Being a word guy, I decided to see what a firkin is.
Here is what my research found. A firkin is a British unit of capacity usually equal to a quarter of a barrel. It is also equal to nine imperial gallons. An imperial gallon is about 1.201 U.S. gallons.
The derivation of the word is Middle Dutch. (vierde fourth plus kin)
Usually, a firkin is a small wooden vessel or tub for butter, lard, sugar, etc.
Typically, the firkin has a lid and handle.
So, now you know the whole firkin story.