Storage Temperature Fluctuation

Chocolate is an emulsion of cocoa solids and cocoa butter. If it is stored improperly, this integral emulsion breaks down, resulting in bloom. Fat bloom occurs when chocolate is stored at high temperatures (above 75°F/23.8°C) or is exposed to wide fluctuations in temperature, causing the cocoa butter to separate from the emulsion and to crystallize on the surface of the chocolate. The ideal temperature for storing chocolate is between 54° and 68°F/12.2° and 20.0°C. The lower temperatures in this range are less risky, because cocoa butter remains tightly bound at the lower temperatures and only gives up its crystal structure when melted at high temperatures.