Oct. 9 (Bloomberg) -- Coffee output in Colombia, the world’s third-largest producer, may increase by as much as 18 percent next year as new crops begin to flower and warmer weather helps boost yields, the head of an exporters group said.

Production may climb to 11 million bags, recovering from a slump caused by excess rain this year, Jorge Lozano, president of Colombia’s National Association of Coffee Exporters, said in a telephone interview in Bogota yesterday.

“With plant renewal, maybe we’ll get to 11 million,” he said. “A lot depends on the weather.”

Colombian growers may harvest as little as 9.3 million bags this year, down 19 percent from the previous season, after above-average rainfall damaged plants, the Colombian National Coffee Growers Federation said yesterday.

Coffee has surged 23 percent this year in New York after heavy rainfall hampered harvests in Colombia and Brazil, the biggest coffee producer and exporter.

Next year’s output will also be boosted by warmer weather that is helping plants flower, Lozano said.

Colombian inventories of coffee, now at about 700,000 bags, probably will increase to 1 million bags within two years, still below historic averages, Lozano said.

In August, Colombian exports slumped 26 percent to 472,000 bags from 642,000 a year earlier, the Bogota-based growers group said last month. Each bag weighs 60 kilograms (132 pounds).