Image adapted from photo by Flickr user Robert House.

What happened

Shares of at-home soda brewing specialist SodaStream International Ltd. (NASDAQ:SODA) surged more than 19% higher in early trading Thursday, before falling back to an 11.8% gain as of noon EST. But why?

So what

If you guessed earnings, then congratulations. You're right! SodaStream reported Q3 earnings this morning, beating Wall Street's estimated $0.24 in earnings on $117.7 million in sales. In fact, SodaStream reported $0.69 per share in diluted earnings, which was more than triple last year's Q3 tally. Revenue grew 12.9% year over year to deliver a $124.2 million surprise to the upside.

Management described the results as "very strong," with CEO Daniel Birnbaum highlighting "a 23% increase in sparkling water maker unit sales to 788,000, our highest quarterly figure in nearly two years."

Now what

That increase in equipment sales -- twice as fast as overall sales growth -- can be read in either of two ways. Referring to the old razor-and-blade business theory, soda-bottle-half-empty investors will point to relatively slower sales of soda-making "consumables" as evidence that SodaStream owners aren't actually using the machines they've bought in years past. They'll say this diminishes the stock's long-term attractiveness. Bottle-half-full folks, on the other hand, will emphasize the faster growth of soda machine "razors" as enabling even greater sales of consumable "blades" in the future.

As for management's view, Birnbaum is pointing to "an all-time quarterly record 7.7 million gas refills" as evidence that the bottle here is actually half full -- and with the stock up considerably more than 10% as of this writing, it looks like most investors agree with him.

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.