Sugar and Fat Bloom
It is not uncommon for a chocolate bar or box of chocolate confections to be opened and the chocolate is no longer shiny. Instead, it looks as if the chocolate has spoiled and is covered with white or light brown colored splotches. While it may look as if the chocolate has spoiled, the chocolate is in fact edible.
What has occurred is that the chocolate has undergone a process called “bloom.” There are two main types of chocolate bloom. The first is sugar bloom and the second fat bloom. Each has different causes. However, no matter the type of bloom, the surface of the chocolate will become unappealing and will have a mottled or hazy look. If fat bloom is present, it is likely that the texture of the chocolate may have changed from when it was originally molded.
Sugar bloom is caused by moisture coming into contact with the chocolate. Chocolate is composed of ground cocoa beans and sugar, and sometimes vanilla and lecithin. While you may not see the sugar crystals present in chocolate, they are there. They simply are too small to see. Water when it comes in contact with the chocolate, dissolves the sugar on the surface of the chocolate. As the water dries, the dissolved sugar crystallizes and precipitates onto the surface of the chocolate. The resulting small sugar crystals give the chocolate a dusty appearance.
The sugar bloom may have occurred in a number of ways. The most obvious of is that water was inadvertently spilled on the chocolate, or the chocolate came in contact with or was placed on something wet. Sugar bloom may occur in other not so obvious ways. For example, if the chocolate was placed in the refrigerator where it became cold and then removed and placed in open air, the cold chocolate will condense moisture from the air, and the condensation will cause the sugar bloom. Sugar bloom may also occur if the chocolate has been in an environment with too high a humidity.
The best way to avoid sugar bloom is to store your chocolate in an area of low humidity and stable temperature so as to avoid condensation. If the chocolate is cold, such as when it has been stored in the refrigerator, it should be covered (perhaps with a towel) so that it will warm slowly and air circulation is minimized.
A Simple Test
One way you can easily check to see if a piece of chocolate has undergone sugar bloom or fat bloom is to lick your finger and touch it to the chocolate. If the dusty appearance disappears, then it is sugar bloom. (The moisture on your finger dissolved the sugar crystals on the chocolate.) If the bloom remains, then it is fat bloom.
Fat bloom, unlike sugar bloom, is not always caused by a simple set of circumstances, such as the chocolate becoming wet. Fat bloom is more complicated, and oftentimes it may be more difficult to discover the actual source of the problem.
Fat bloom typically appears as lighter color spots on the chocolate. As the name implies, the bloom is composed of fat, in this case the naturally occurring fat that comes from the cacao bean — cocoa butter.
When discussing the reasons for fat bloom, it is important to note that when
cocoa butter hardens, it forms crystals. Some of the crystals are stable, but other crystals are not and will actually change form over time. During chocolate manufacturing, a process calledtempering is used to ensure that only stable crystals form, while the chocolate hardens. Fat bloom is caused by the interaction of the various types of crystals or the tempering process (or lack thereof).
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