Acid levels have fallen in recent weeks but remain above European Union standards in the world's top grower because of a lack of rain while bean sizes remain small.

Bean acidity is measured by free fatty acid (FFA) levels, which when high erode the quality of cocoa butter. FFA levels were around 3 percent this week, growers said, above the E.U.'s 1.75 ceiling. FFA levels had reached as high as 5 percent in recent weeks, causing some grinders to reject the beans.

"Generally speaking, the quality is not yet good even if the FFA is now towards 3 percent," said the director of an international export company.

Bean size is also a problem, in part due to the heat which has hit development of pods.

Reuters found that bean counts in the main production areas of Daloa, Vavoua, Duekoue, Soubre, Bouafle and Issia weighed in mostly between 130 and 140 beans per 100 grams, higher than exporters' expectations of around 110 beans per gram.

"We think that the quality will change towards July but for now the grainage is too high," said Fousseni Coulibaly, a pod counter in Duekoue. "It's better than last year, but we expected better."