It's not every day that a company reports a 906% year-over-year increase in quarterly net income. One would think that such explosive growth would create quite a stir for the stock of that firm. In fact, that is exactly what has happened for the shares of the company in question, MGP Ingredients (NASDAQ:MGPI). The stir, though, is very much in the downward direction, as shares slid more than 8% in recent trading.

The apparent reason for the current nose dive is that, while MGP's earnings were good, they were not as good as had been expected. The firm's $0.43 per diluted share earnings were $0.03 shy of the consensus estimate as reported by Reuters.

Such a sell-off might be deemed overblown, especially considering the vast improvement in the food ingredient specialist's earnings. But it might be best not to jump on MGP's shares as a bargain. A closer analysis of the company's position suggests that its growth spurt might be short-lived.

MGP's jump in the bottom line was driven by its distillery segment, which saw revenue surge 51% to $71.6 million thanks to strong pricing for ethanol and food grade alcohol products. Meanwhile, the firm's ingredients unit saw revenue plummet by almost 30% to $18.7 million. Sales in certain specialty proteins and starches actually were up for the quarter, but the loss of the firm's main customer for the Chewtex line of pet-related products badly hurt the unit's performance.

Unfortunately for MGP, it's not clear that strength in the distillery segment is sustainable, especially with respect to ethanol sales. With Archer Daniels Midland (NYSE:ADM), the country's largest ethanol producer, bolstering ethanol production and new entrants like VeraSunEnergy (NYSE:VSE) also bringing more new capacity online, ethanol prices seem headed for a downswing.

Granted, MGP's ethanol business isn't going to evaporate, given continued government subsidies and promotion of the alternative fuel by automakers like Ford (NYSE:F). But for MGP to keep up its growth, it needs to get its ingredients business in gear.

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Fool contributor Brian Gorman does not own shares in any of the companies mentioned.