Buyers of coffee from http://topics.bloomberg.com/vietnam/>Vietnam >, the world’s biggest grower of the robusta variety, are paying a smaller premium for their beans after futures prices in London climbed, according to trading company NC Group Ltd. Vietnamese coffee for immediate shipment was at a premium of $5 to $10 a metric ton to the price of the September contract on the NYSE Liffe exchange in London, the trader said in a report e-mailed today. That compares with $20 a ton on July 2. Robusta coffee for September delivery advanced 2.7 percent over the past week in London. The “differential level eased back $10 to $15 due to the recent increase in the terminal price,” Nguyen Chi Cuong, chief executive officer at the company, which has a trading office in http://topics.bloomberg.com/ho-chi-minh-city/>Ho Chi Minh City >, Vietnam, wrote in the report. Differentials refer to a premium or discount to obtain physical coffee in relation to the futures price. Robusta futures climbed as arabica coffee advanced on speculation rains that are delaying the harvest in http://topics.bloomberg.com/brazil/>Brazil >, the world’s biggest coffee producer, will damage the beans, lowering their quality. Arabica coffee rose 8.9 percent in the past week on ICE Futures U.S. in http://topics.bloomberg.com/new-york/>New York >. “London coffee has almost become a forgotten uncle over the last few sessions as New York takes all the glory,” London- based futures and options broker Sucden Financial Ltd. said in a daily report e-mailed yesterday. “Gradually, robusta prices improved, almost reluctantly in New York’s shadow.” Arabica coffee is grown mainly in http://topics.bloomberg.com/latin-america/>Latin America > and is favored for specialty drinks such as those made by http://www.bloomberg.com/quote/SBUX:US>Starbucks Corp. (SBUX) > Robusta beans, harvested mainly in Asia and parts of http://topics.bloomberg.com/africa/>Africa >, are used for instant drinks and espresso. NC Group was established in 2004 and trades natural rubber and coffee. The company sells 80,000 to 150,000 bags of coffee a year. Cuong was previously a coffee trader in Vietnam with Noble Group Ltd. Source: http://www.bloomberg.com/news/2012-07-04/vietnam-s-coffee-premium-drops-as-london-futures-advance.htm