November 19, 2004
August 1, 2006
Blooming occurs in two forms: cocoa butter bloom and sugar bloom. Both occur when chocolate has been subjected to impoper storage.
Chocolate is an interesting substance and behaves very similarly to other tempered products, such as steel, due to the nature of the crystallization. When melted, the crystals needs to be re-formed in a controlled manner to achieve a stronger structure and prettier appearance. Fat bloom occurs when the temperature is too warm, which thereby causes the chocolate to melt...cocoa butter and all. This uncontrolled melting destroys the bonds held by the crystals, and when the resulting mass is cooled again in an uncontrolled manner, the cocoa butter, cocoa liquor, sugar, etc. will re-form unevenly and cause those white streaks and swirls. This is why tempering is so important. Chocolate suffering from fat bloom is still edible and suffer no loss in flavor. It simply needs to be tempered.
Sugar bloom occurs when moisture condenses on the chocolate's surface and evaporates, which thereby leaves the sugar scattered on the chocolate's surface, which is visible in those gray patches. Chocolate absorbs moisture from the air, especially if the moisture content is above 85%. So the ambient room temperature needs to be below 68 F with little moisture, preferably below 50%. Chocolate suffering from sugar bloom, however, can tend to be grainy and a little dry. Some people might argue this, but personally, I've tried sugar bloomed chocolate that was horribly dry and and grainy.