Arabica coffee and US cocoa futures also climbed, but only modestly, while London's cocoa and robusta coffee inched lower.
The commodity complex rebounded after the dollar plunged to a record low against the Japanese yen on speculation authorities will not halt the yen's surge, and while fresh austerity moves by Spain helped dampen fears about Europe's debt crisis.
"I think the only trade people are really interested in for the softs today is sugar," said Hector Galvan, senior market strategist for brokerage RJO Futures in Chicago.
"I think today has given (market participants) the opportunity for them to do what they've been wanting to do, and that's buy the sugar (market)."
ICE October raw sugar futures vaulted up 1.84 cents, or 6.3 percent, to settle at 30.96 cents a lb, a three-week high, paring gains slightly after climbing as high as 31.18 cents.
"You have an improved technical picture along with a weaker dollar boosting sugar," said Country Hedging Inc analyst Sterling Smith, adding sweetener values are buoyant despite the shaky performance of equity markets.
The market has climbed more than 18 percent in just under two weeks.
The Brazilian cane crop hounded by poor yields from aging plants will likely get smaller in the months ahead, cash brokers believe Chinese buying will pick up as Beijing seeks to restock, and there are persistent questions India will be able to export as much sugar as it had earlier announced.
Brokers reported talk that China, which is expected to become the world's No. 1 raw sugar importer in 2011/12, could authorise extra import quotas to relieve soaring domestic prices and low reserves.
"Inflation is now a global concern," said Smith, adding many in the trade believe New Delhi may again balk at allowing so much sugar to be exported if food inflation again becomes an issue in the populous South Asian nation.
Stock levels in China and India were also low, leading traders to feel that the Chinese will book orders and the Indians may hold back a bit on exports to build up their sugar inventories.
Sugar futures were lower earlier in the session when there were concerns the US economy could slip back into a recession and European banks could face more credit concerns.
October white sugar futures on Liffe rose $21.10, or 2.8 percent, to finish at $786.90 per tonne.
Coffee dealings were choppy, caught between spillover support from the strong equity markets and commodity complex, and pressure from origin selling above the 100-day moving average around $2.6910 per lb.
ICE December arabica futures rose 1.45 cents to settle at $2.6985 per lb, above the 100-day moving average for the first time since June 14. November robusta coffee on Liffe dropped $5 to finish at $2,300 per tonne.
Cocoa futures on ICE firmed on short covering, dealers said, counteracting earlier pressure due to risk aversion in financial markets and as upward revisions to West Africa's 2010/11 crop weighed on prices.
A record 2010/11 global surplus is expected after ideal weather and increased husbandry triggered a bumper West African crop.
December cocoa on ICE closed up $19 at $3,004 per tonne, while Liffe December cocoa finished up 1 pound at 1,889 pounds per tonne.
Copyright Reuters, 2011