NEW YORK (MainStreet) – It isn't quite October yet, but beer geeks know that it's been Oktoberfest for more than a week now.

The official Oktoberfest proceedings in Munich kicked off September 20 and aren't slated to end until Sunday. Meanwhile, Oktoberfest celebrations in Cincinnati; Denver, New Ulm, Minn., LaCrosse, Wisc.; Mount Angel, Ore., Levenworth, Wash.; Torrance, Calif.; Hermann, Mo., and elsewhere have either come and gone or have just begun.

While the German celebration dates back to 1810 and the wedding of King Ludwig and Princess Therese of Saxe-Hildburghausen, it is connected to various festivals celebrated by 46 million U.S. citizens of German descent by a thin river of beer. Adolphus Busch, Joseph Schlitz, Frederick Pabst and Frederick Miller, August Schell, David Jüngling (later Yuengling) -- all those pioneering brewers draw their lines back to the tide of German immigrants who entered the U.S. in the 19th Century. They brought a brewing tradition with them, but they'd also bring the Oktoberfest lager known as Märzen.

By their most stringent definition, Oktoberfest beers are supposed to be brewed according to the German Reinheitsgebot law of beer purity -- which dictates that only hops, malted barley and water (and, eventually, yeast) can be used to brew beer. Also, those beers are supposed to be brewed within Munich, which meant only Spaten, Löwenbräu, Augustiner-Bräu, Hofbräu-München, Paulaner and Hacker-Pschorr brewed “official” Oktoberfest beers.

However, that doesn't mean those beers were brewed with any consistency. Though they're still brewed in March and are left to ferment in cold storage through the summer, today's Oktoberfest bears little resemblance to the dark or even amber Märzen of years past. If you see photos of waitresses at Oktoberfest carrying mugs of frothy, golden beer, that's pretty much what Märzen looks like today.

That isn't necessarily true in the U.S., however, where both traditional and craft brewers have experimented with original recipes and tinkered with Märzen to their taste throughout the years. Märzen, or Oktoberfest, is now part of a seasonal beer slate that makes up 15% to 25% of the more than $19.6 billion in annual craft beer sales, according to market research firm IRI.

With Oktoberfest upon us and more than 3,700 U.S. brewers producing hundreds of takes on the Märzen style, we've selected just ten to get you started:

Hofbräu Oktoberfest

Various Hofbräuhaus locations

Alcohol by volume: 6.3%

Of all the Munich breweries that produce Märzen, only one decided to franchise itself throughout the United States. Back in 2003, Hofbräu Müchen decided to open its first Hofbräuhaus location in the U.S. in Newport, Ky. -- a city with a deep German brewing heritage located right over the Ohio River from Cincinnati and its Over-the-Rhine brewing district. Franchises followed in Las Vegas, Pittsburgh, Chicago, Cleveland and Columbus -- not including a beer garden in Panama City, Fla., and the Bierhaus pub in New York. As for the beer itself? Well, let's just say it's true to the modern Munich interpretation: crisp, mild and on the lighter side. That isn't necessarily a bad thing when you're drinking it a liter at a time.

Schell's Oktoberfest

August Schell Brewing Company, New Ulm, Minn.

Alcohol by volume: 5.5%

Schell brewer David Berg gets surly and downright defensive about his lager, and who can blame him? Since 2006, he's made beer for a brewery whose founder not only co-founded the city it's based in with a whole lot of other recent German immigrants in 1856, but brewed its first batch of beer in 1860. Despite this, the Brewers Association craft beer industry group declared his brewery “not craft” until just last year, when it finally changed its mind about what constituted “traditional” ingredients.

You'd think a brewery that coasted through Prohibition on low-alcohol beer, soda and candy production would know a little bit about that, but they never aged a triple IPA in a sherry barrel, so what do they know? Well, it turns out that they know how to brew an amazing copper Märzen with just the right biscuit-and-baguette mix of Pale, Munich, and Cara Pils malt to compliment the subtle peppery spice of Liberty and Perle hops. If you're in the area on October 10, stop in for the Oktoberfest festivities, listen to the brewery's Hobo Band that's been around in one form or another since 1948 and enjoy the newest 155-year-old craft beer in the country.

Yuengling Oktoberfest

D.G. Yuengling & Sons, Pottsville, Pa.

Alcohol by volume: 5.4%

This brewery has been brewing in Pottsville, Pa., for more than 185 years. It survived Prohibition by turning itself into a dairy and is the fourth-largest brewer in the nation even though it's distributed in only 15 states and Washington, D.C. However, despite all of that, the Brewers Association only got around to considering it a “craft brewer” last year.

At some point, if you're a pre-Prohibition brewer of German heritage, you start to take this kind of thing personally. Grated, Yuengling doesn't do a whole lot of things that “craft” folks like. It has two light beers in its portfolio and its year-round beers -- with the exception of its Chesterfield Ale, Porter and Black & Tan -- consist primarily of light lagers.

However, in recent years, the folks at Yuengling have branched out a bit and dove into their brewing heritage. Oktoberfest was introduced in 2011 and doesn't stray that far from the company's core offerings. It's darker and way more biscuity than Yuengling Lager, as Märzen tends to be, but it's still in keeping with the rest of the brewery's offerings.

Yuengling has compiled nearly two centuries of history without drifting on whim. It's embracing seasonal beers on its own terms, which means lagering, darker Oktoberfest beers and a return to traditions that “craft” is just getting around to embracing.

Oktoberfest

Sierra Nevada Brewing Company, Chico, Calif.

Alcohol by volume: 6%

Ken Grossman and his team at Sierra have been big into lagering of late. Their Nooner low-alcohol session beer is a pilsner. Their summer seasonals included a Summerfest lager and a Kolsch. However, their biggest surprise of all was this year's ridiculous Oktoberfest collaboration with Brauhaus Riegele of Augsburg. A light base of bready pale and pilsner malt joins German Steffi malt and a biscuity Munich to blend nicely with the slight bite of German Magnum hops and the spicy finish of German Tettnanger, Spalter and Select hops. The result is a golden-copper dream of an Oktoberfest that hits the sweet spot between the modern pale Märzen and the darker, sweeter version that too many other brewers turn syrupy sweet. We've been hard on craft brewers throughout this list, but this is evidence of what they can do when they hew to tradition and actually consult the Germans.

Samuel Adams Octoberfest

Boston Beer Company, Boston

Alcohol by volume:

A whole lot has changed since this beer was first brewed in 1989.

Boston Beer Company is best known for its Samuel Adams line of beers, but it's now an umbrella for multiple operations. Beer only accounts for about 2.9 million barrels of Boston Beer's overall production, with its Angry Orchard cider line taking up much of the rest. The company also drifts into the flavored-malt-beverage portion of the beer aisle with its Twisted Tea products and recently started producing a line of beer-and-soda shandies under its Traveler brand. Even Samuel Adams itself drifted from its Boston Lager and more Teutonic styles and into a line of IPAs.

However, this beer serves as a reminder of Boston Beer's deep roots in German brewing. Boston Beer once swore by the Reinheitsgebot. Since 1985, Boston Beer founder Jim Koch has teamed with the world's oldest brewery, Bayerische Staatsbrauerei Weihenstephan, on the champagne-style Infinium beer and has maintained a decades-long business relationship with German and hop suppliers to procure German heirloom hops (at one point, Boston Beer was the largest buyer of Hallertau Mittelfreuh hops and helped revive the variety). Just last year, he was awarded the Bavarian Order of Beer at the Brau Beviale global beer trade show: Making him the first non-German to receive the award in its 35-year history.

Because of all of the above, and in deference to the German tradition of reserving the Oktoberfest title for Munich beers, Octoberfest dropped the k for the c and went a bit maltier with its formula. That's allowed Octoberfest to hold its own as a fragrant, flavorful fall favorite whose caramel-and-biscuit aroma hangs in the air during tours at the Samuel Adams research and development brewery in Boston around this time each year. Since this beer was first brewed, other craft brewers took it as their cue to ratchet up the sweetness on their own Märzens. However, this balance of sweet Caramel and Munich malts with spicy Tettnanger and Hallertau Mittlefruh hops may be the last time a brewer tried to find some middle ground between this style's tradition and modern tastes.

FestBier

Gordon Biersch Brewing Company, San Jose, Calif.

Alcohol by volume: 5.6%

Gordon Biersch head brewer Dan Gordon knows just a little bit about German brewing tradition. While studying in the German town of Gottingen, he toured the nearby Einbecker brewery on several occasions and greatly enjoyed the Maibock it first made in the 14th Century. That experience led him to his graduate studies at the Technical University of Munich and inspired him to found Gordon Biersch with a business partner.

As a result, he's also aware that Munich's Oktoberfest was held in the middle of October. However, Munich's brewers got it in their heads that if they moved the date to the last week of September through the first week of October, they could sell more beer in the warmer weather. When they reached that realization they also created the modern Oktoberfest beer with its lighter body -- unlike the somewhat fuller Märzens. They also gave it a bit more hop character, which Gordon attempted to recreate by combining dark-roasted Munich malt and pilsner malt with Hallertau and Tettnang aroma hops. The hop scent is faint, but the Munich malt makes this just a shade darker and a touch sweeter than the lighter Festbiers Gordon was shooting for. That isn't necessarily a bad thing.

Shiner Oktoberfest

Spoetzl Brewing, Shiner, Texas

Alcohol by volume: 5.7%

Brewed in the 105-year-old Spoetzl Brewery in Shiner, Texas, and distributed in 48 states, Shiner has grown astronomically since Carlos Alvarez brought the brewery into San Antonio-based Gambrinus in 1989 and started trading in on its boots-and-barbecue Texas ties. While the flagship Shiner Bock is still what many beer drinkers outside of Texas think of when they hear the Shiner name, Shiner's Oktoberfest Marzen has held its own since 1996 and was featured as a limited-release beer to celebrate Spoetzl Brewery's 96th anniversary in 2005.

It's a faithful representation of the copper, biscuity Märzens of yore. In fact, the judges at the 2012 Great American Beer Festival in Denver thought highly enough of it to award it a gold medal in the German-Style Marzen category. That's a testament to Spoetzl's German brewing heritage and to Shiner's unwaveringly traditional take on seasonal beer. Don't put a pumpkin or a cinnamon shaker anywhere near this one.

Ramstein Oktoberfest

High Point Brewing Company, Butler, N.J.

Alcohol by volume: 6%

New Jersey's craft beer is a mess. Its number of breweries (less than 40) is woefully inadequate for the most densely populated state in the union, ranking it 48th among all states in breweries per capita. Its draconian, slowly evolving beer laws have made it a blend of '90s-era brewpubs and production brewers and recent upstarts including Carton, Kane and Forgotten Boardwalk.

However, for nearly 20 years, High Point and its Ramstein brand have been a constant amid the chaos. Started by German-trained brewer Greg Zaccardi, who named the line after the German city that houses a U.S. airbase of the same name, Ramstein has bravely attempted to bring traditional German styles to a state that regularly crosses into Pennsylvania for such things. As a result, Ramstein Oktoberfest has spent years becoming perhaps the best example of the traditional Märzen that you can find East of the Delaware but West of the Atlantic. Heavy on the dark Munich and caramel-flavored malts, but not so heavy that it drowns out the blend of German hops, Ramstein Oktoberfest is one of the big reasons High Point has persevered. Evolving from a small local anomaly to a packed house of growler-toting stalwarts, High Point crested its second craft beer wave by sticking to what it does best and attracting the talent to keep those technically complex styles flowing.

Staghorn Octoberfest

New Glarus Brewing Company, New Glarus, Wisc.

Alcohol by volume: 6.25%

Yes, this beer is brewed in what looks like an Alpine village. But despite the fact that more than 70% of Wisconsinites are of German heritage, New Glarus was founded by and is still home to a whole lot of Swiss. You know, folks from the neutral country that has endured so much trouble from its neighbors (including Germany) over the years that it's basically a nation-sized mountain fortress?

But this is Wisconsin, and these are different times. The folks at New Glarus Brewing have made an incredible Bavarian Märzen by loading up on the amber malts, giving it a thick, rich body that comes through in this beer's frothy head and piling on the German hops to give it an herbal finish that nips the malt sweetness before it gets to be too much. While Oktoberfest in New Glarus can be a wonderful lesson in both European history and geography, it's also a reminder not to judge a Bavarian Märzen by its Swiss surroundings.

The Kaiser

Avery Brewing Company, Boulder, Colo.

Alcohol by volume: 9% to 10%

To put it succinctly, The Kaiser lacks subtlety.

From the name to the really high potency for what's supposed to be a daylong beer, The Kaiser does a fairly horrible job of embodying the tradition of its style. Then again, it's brewed in Boulder, the cradle of the U.S. craft beer and homebrewing movements and the home of the Brewers Association. This beer and the people who made it exist to push limits.

Labeled an “Imperial Oktoberfest,” the Kaiser comes only in 22-ounce bottles and is layered with dark, sweet Vienna, Munich and Dark Munich malts. How sweet is it? Well, those malts produced enough sugar that the yeast feeding on it basically gave this beer an alcohol content almost double that of an average Märzen. Copper with just enough Bravo, Tettnang, Hersbrucker hops to let you know they're there, Kaiser makes the end of this list simply because we'd only recommend drinking it as a nightcap to a long day under the beer tent.

This article is commentary by an independent contributor. At the time of publication, the author held TK positions in the stocks mentioned.