The Beers
Six breweries, all from Munich, operate at the Oktoberfest.
The below focuses on the 14 large tents. The Oktoberfest breweries also sell at various smaller tents and food stalls around the grounds of Oktoberfest.
Lowenbrau
Brewed in Munich since 1383. You'll have heard of this in the U.K. and it's everywhere you go in Munich.
Lowenbrau can be found at the Lowenbrau Festhalle and Schützen Festzelt.
Lowenbrau is top quality, they sell it in cans at Makro. Lowenbrau Oktoberfest bier is sold at ALDI every September/October.
Hofbrau
I love Hofbrau Oktoberfest bier, it's delicious! Hofbrau commenced brewing in Munich during 1589. It's government owned and was the beer of choice for the Nazi party! Don't worry, a couple of these and you won't be able to find Poland!
Hofbrau can be found at the Hofbrau Festzelt only.
Augustiner
Strong, tasty and the favourite with the Munich locals. Brewing since 1328, it's Munich's oldest brewery.
Sold at the Augustiner Festhalle and Fischer Vroni.
Paulaner
A great beer whether you try the hell (normal clear lager) or the weiss beer. The Paulaner monks started brewing in 1629.
Paulaner Hell is sold in Tesco! Armbrustschützen-Festhalle, Winzerer Fahnd'l, Käfer's Wies'n Schänke and Weinzelt.
Hacker-Pschorr
Another one that I rate very highly (surprise!) Hackerbrau (started brewing in Munich during 1417) and merged in 1793 with Pschorrbrau when Joseph Pschorr married Mria Theresia Hacker and then bought the brewery off his new father in law.
Sold at the Hacker Festzelt and Braurosl. You can get normal Hell beer or Oktoberfest Marzen (a dark beer, like a really tasty ale).
Spaten
Spaten have been brewing in Munich since 1397. Spaten is sold at the Hippodrom, Schottenhamel Festhalle and the Ochsenbraterei.
They sell this in ALDI too!