The Oktoberfest style of beer actually predates the first Oktoberfest celebration of 200 years ago. The other name by which this ancient style is known gives us a hint of its true roots: Märzen.
In the days before refrigeration, it was nearly impossible to brew quality beer during the hot summer months. Instead, Germans brewed beer for the summer in March (or Märzen) and then stored the beer in cellars and caves filled with ice. The last of these batches were typically consumed in October, in time for the barrels to be reused for fall brewing. Eventually, inclusion of the style in Oktoberfest festivities became a natural fit.
The characteristics of the Oktoberfest/Märzen style were also shaped by history. Beers with higher alcohol levels preserve better and, as a result, Oktoberfest beers typically register a healthy 5-7% alcohol by volume. While a decent amount of hops are also used to help preserve the beer, after aging for three or four months the beer will mellow to have a decidedly malty tilt.
For the best representatives of the style we'll start, of course, in Germany, with a brewery that traces its roots back to Munich in 1417. HACKER-PSCHORR'S ORIGINAL OKTOBERFEST is deep red in color with a husky malt aroma that is distinctly German. The flavor is of nutty and caramel malts, but has a light, silky mouthfeel that allows one to drink another. Another personal flavor is PAULANER'S OKTOBERFEST- MÄRZEN. The toasted malts have a little more heft to them, but a balanced flavor also provides drinkability.
SPATEN OKTOBERFESTBIER UR- MÄRZEN is another widely available German Oktoberfest, albeit a fairly one-dimensional one with a building sweetness. AYINGER'S OKTOBER FEST- MÄRZEN is a little better with malts that taste fresh and crisp, a lighter body, and cleaner mouthfeel. WEIHENSTEPHANER FESTBIER is unquestionably the most unusual Oktoberfest I've had from Germany, with far more bitterness than a typical Oktoberfest. Still an enjoyable beer, but hardly true to style.
But what about the proliferation of American-brewed Oktoberfest beers? Now-adays it seems nearly every craft brewer makes an Oktoberfest, with a great deal of variation across the style. I think PORTSMOUTH'S OCTOBERFEST best follows the spirit of its German brethren with its ability to check the bready malts with some light herbal hops. This helps to create the lightness and drinkability you need in an Oktoberfest. My other favorite is BERKSHIRE'S OKTOBERFEST LAGER with its sweet, slightly spiced nose. Indeed, this seems to aspire to be a pumpkin beer, and a robust one at that with 6.8% ABV! Berkshire is certainly pushing the limits, but I love this beer.
Other options worth picking up include the strong but balanced THOMAS HOOKER OCTOBERFEST LAGER. LEFT HAND'S OKTOBERFEST has a more traditional maltiness, but stops short of being overly sweet. While a step below any of these four, SAMUEL ADAMS OCTOBERFEST, HEAVY SEAS MÄRZEN, and VICTORY FESTBIER are undoubtedly all readily available at your local package store. Move quickly if you haven't gotten your fix of Oktoberfest beers yet — winter warmers are right around the corner.