By Julie Wernau 
 

Coffee prices rose Thursday on fears that dry weather in some coffee-growing regions could lead to shortages.

Vietnam and Indonesia, the world's first- and third-largest growers of robusta coffee, a bitter bean variety typically found in coffee blends and instant coffee, warned that dry conditions caused by the El Nino weather event are intensifying, threatening crops there.

At least one trading firm has built up a large position in the July robusta contract, which is traded in London, and that has some investors anticipating higher prices and making the switch to the more mild-flavored arabica bean, brokers said.

Arabica coffee for September delivery rose 2.4% to $1.251 a pound on the ICE Futures U.S. exchange.

"If you can't grab from one pile, you go and grab from the other," said Hector Galvan senior broker at R.J. O'Brien Futures in Chicago. "Even though they are different types of coffee, when you have short falls in one market, you'll see the other one rally."

In other markets, raw sugar for October was up 0.2% to 11.48 cents a pound, cotton for December fell 0.3% to 63.72 cents a pound, cocoa for September rose 0.1% to $3,220 a ton and frozen concentrated orange juice for September rose 0.6% to $1.235 a pound.

Write to Julie Wernau at julie.wernau@wsj.com

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