It wasn't exactly a frothy pint that brewers Molson Coors (NYSE:TAP) and Boston Beer (NYSE:SAM) were reporting this week, and investors were left wrinkling their noses as a result.

While beer sales in general have been edging up -- they rose 1% for the first half of the year, according to the beer trade group Brewers Association -- the craft beer category has seen the greatest growth, rising 11% over the first six months. That wasn't enough to help Boston Beer or Molson Coors, both of which were skunked by investors as costs weighed on operations.

Molson Coors reported that although U.S. volume rose 3.4% for the quarter, which allowed it to gain market share, overall volume was lower because of slack European sales. Cool, rainy weather apparently prevents Europeans from cracking open a bottle, but so did new bans on pub smoking. Sales volumes were also off in Canada because of the timing of the Canada Day holiday - it fell during last quarter, which helped make returns frothier then. Higher operating costs in the U.K. hurt profits, which slipped 1% to $134.7 million, or $0.74 per share.

It was grain costs and expenses related to a federal audit that caused Boston Beer to go flat. The maker of Samuel Adams said the cost of barley, hops, and packaging materials, as well as a temporary shutdown of a Cincinnati brewery for maintenance, had eaten into profits. More troublesome, though, is an ongoing audit by the federal Alcohol and Tobacco Tax and Trade Bureau. A contingent set aside for excise taxes of $3.9 million swiped $0.18 a share from profits, and the figure may go higher. Investors dumped shares of Boston Beer like they were infected with ergot, and the stock fell 25% in one day.

While investors were underwhelmed by the batch of earnings brewed this quarter, the earnings of Molson Coors should actually give pause to Anheuser-Busch (NYSE:BUD), which will soon face a formidable foe in the form of a Molson Coors-SABMiller joint venture. MillerCoors will have some $6.6 billion in combined U.S. revenue. And while it will still have a long way to go to dethrone the King of Beers, which has more than $11 billion in domestic revenue, the marketing muscle and greater distribution channels ought to help it claw its way up in a tight beer market.

Bud, though, isn't content to let any pretenders to the throne challenge it without a fight. It reported earnings the other week that showed the king still has strength left in its sword hand, with rising sales, widening margins, and increased market-share gains, as well.

The jousting for position will continue, but with Boston Beer trading at a premium to the market multiples of Molson Coors and Anheuser-Busch, we might yet see the patriot brewer thrown from his horse yet again.

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Fool contributor Rich Duprey cries in his beer often, but does not have a financial position in any of the stocks mentioned in this article. You can see his holdings here. The Motley Fool has a disclosure policy.