Firkin Madness!

It's firkin madness at The Porter this week, which sounds great, but then you realize you don't know what a firkin is or why you should care.  I'll start by saying that you should care because it means you're drinking a fresh, naturally carbonated, living ale.  There's not loss of flavor from filtering (meaning the beer will be cloudy) and they are served room temperature to let all the flavors be more fully released.  I assume there's only one firkin of each beer (9 imperial gallons), so they'll probably go fast, which is good because once a gravity drawn firkin is tapped they have very limited shelf life.  Here's the schedule.  I'm looking forward to the Lenny's.

Tuesday-Bell's 2 Hearted Ale
Wednesday-Allagash Black
Thursday-Lenny's RIPA
Friday-Heavy Seas Hop^3

If you care what a firkin is you can read after the jump.

At its most basic, a firkin is a 9 imperial gallon cask.  You don't care what it is or how big the container is though.  You care about firkins because of what they are not.  Beer was stored and served the same way for centuries.  After it was brewed it was moved to a second container with additional yeast and sugar and underwent a secondary fermentation, which is how it got its carbonation.  It would either be hand pumped from a cask or gravity drawn, but wither way there was no carbonation added and it was alive when you drank it.

Having a living beer may be great for taste, but it made storing beer difficult.  When pasteurization was discovered many beers started getting flash heated, killing anything alive, including the yeast.  It's the second fermentation that gives the beer most of the carbonation though.  The arrival of the keg solved this problem and the problem of beer spoiling after being exposed to oxygen for too long.  In a keg the beer is forced out by CO2, which artificially carbonates the beer and keeps the remaining beer from being exposed to oxygen.

These developments mean that most of the beer that you drink on tap now has been killed, filtered, and finally had CO2 forced into it, all of which will significantly alter the taste and feel of the beer.  There is no pump on these firkins.  They lay on their side, and there is a spout on the bottom for the beer to come out and a hole on top for air to enter and equalize pressure.  There's no CO2 being pumped into the cask carbonating and forcing the beer out.  What you are drinking is beer as it was drunk for centuries, with nothing getting in the way of the flavor the brewer intended.

See more here.