Global sugar demand was forecast to rise 1.5 percent next year, in line with the five-year average, Societe Generale said in its Commodities Outlook report.
"Going forward, Brazil's sugar-ethanol parity floor will remain a key driver of sugar prices, especially in the context of under-hedged Brazilian sugar production in (marketing year) 18/19, and retracing energy prices will weigh on sugar prices," Societe General said.
The bank pegged raw sugar prices to fall to 14.4 cents per lb in its six-month forecast. The spot futures contract settled up 2.7 percent at 15.28 cents per lb on Wednesday.
In coffee, Societe General forecast a supply surplus of 6.3 million bags of arabica in 2018/19 and a deficit of robusta of 3.4 million bags.
Arabica coffee prices were forecast to average $1.30 per lb in six months, up slightly from Wednesday's benchmark contract settlement at $1.27.
Robusta coffee was pegged rising to $1,850 per tonne amid strong global exports and record inventory levels in major consuming countries.