Sweet could get expensive. Raw sugar prices may rise to the highest level in more than 30 years by March, if dry weather hits the Brazilian sugar crop, broker Newedge USA told Bloomberg News.

Sugar prices have more than doubled since May on concern about output in Brazil, Russia, China and Pakistan.

"If there's less rain than normal in Brazil until March, you could potentially see a reduction in the cane harvest, and then you have a potentially big problem," Michael McDougall, a senior vice president at Newedge, told Bloomberg News.

Also, India may curb its sugar exports as it tries to rebuild its reserves, pushing prices higher. The reserves are currently less than half its preferred level of 10 million metric tons.

"Current prices show that the market needs Indian sugar," McDougall told Bloomberg News.