Sugar futures, supercharged by talk of a switch by Brazilian mills to making cane rather than the sweetener, bounced nearly 5%, leading a rally in agricultural commodities.
Futures in many crops soared on Wednesday, amid a rally in risk assets after a senior member of the US central bank, the Federal Reserve, signalled fresh stimulus for the world's biggest economy may be on the agenda.
Dennis Lockhart, the president of the Atlanta Federal Reserve, said that "further monetary actions to support the recovery will certainly need to be considered" if the US economy stalls.
He added: "It is my sense that material risks to the outlook are gathering."
The comments revived investor sentiment sapped by a refusal by the European Central Bank, at a meeting of its governing council, to unveil fresh economic stimulus, leaving its benchmark interest rate unchanged at 1%.
Shares stood 1.8% higher on Wall Street in lunchtime deals, after closing up more than 2% on Europe's main exchanges.
|Ag commodity prices, 18:20 UK time|
New York raw sugar: 19.92 cents a pound, +4.5%
New York cotton: 69.89 cents a pound, +4.5%
Chicago soybeans: $13.82 ¾ a bushel, +2.5%
Chicago corn: $5.80 ¾ a bushel, +2.3%
Chicago wheat: $6.21 a bushel, +1.3%
Prices for July contracts
Dollar-denominated commodities had the extra boost of a slump of 0.7% in the value of the safe haven of the greenback against a currency basket, so boosting their competitiveness as exports.
Wheat recovered 1.3% in Chicago, where corn and soybeans gained more than 2%.
In New York, raw sugar did better still, soaring 4.5% to 19.92 cents a pound, a rise which, if held to the close, would mark the sweetener's strongest trading day since January 3.
The price rise was helped by an appreciation in the Brazilian real, which has regained more than 2% against the dollar in the last two trading days, after depreciating 13% since March.
Recent weakness in the real has been a key factor in the decline of New York sugar futures on Monday to their lowest in 21 months, in shielding Brazilian producers from the decline in dollar prices, while depressing too values of other crops, such as coffee, in which the country is strong.
Furtermore, forecasts for rains in Brazil boosted values, in promoting speculation of a slowdown in a cane harvest already running well behind last year's.
However, sugar's revival was also stoked by a calculation by Job Economia that mills were now - unusually - better off producing ethanol than sugar from cane.
Ethanol vs sugar
"With the exception of the start of the 2011-12 crop period, when there was a lack of product, this is the first time since January 2009 that anhydrous ethanol has been on a par with sugar prices," the Sao Paulo-based consultancy said.
"This may change the product mix in the current crop period," with mills preferring ethanol to sugar.
"The anhydrous ethanol price and [raw sugar] price are about equivalents to the producer in the Centre South region," which grows approaching 90% of cane in Brazil, the top sugar producer.
The ethanol-sugar switchover point has long been viewed as setting a floor to prices of the sweetener, and was broadly considered at being around 19-20 cents a pound, although many analysts have been reluctant to call it because of the complicating factor of the real's depreciation.
Separately, Rabobank analyst Andy Duff said that ethanol was still "marginally more remunerative than ethanol for Brazilian millers" as of the end of last month.