There are two potential issues that can occur with all products containing cocoa butter and dark brown muscovado sugar. Both of them result in pale yellow or white spots on the surface of the product and they are called fat blooming and sugar blooming.
SUGAR BLOOM is caused by moisture coming into contact with the product. WoMn Vanilla&Lemon scrub is composed of fine dark brown sugar mixed with butters, oils and emulsifier. Water, when it comes in contact with this kind of product, dissolves the sugar on the surface. As the water dries, the dissolved sugar crystallizes and precipitates onto the surface of the scrub. The resulting sugar crystals give the scrub a characteristic white spots or granules on its surface. Those granules are hard on touch and with clearly defined edges opposite to molds that are soft on touch and with soft edges.
The sugar bloom may occur in a number of ways. The most obvious of them is that water was inadvertently spilled on the scrub, or the scrub came in contact with something wet. Sugar bloom may, also, occur in other not so obvious ways. For example, if the scrub was placed in the refrigerator where it became cold and then removed and placed in open air, the cold scrub will condense moisture from the air, and that condensation will cause the sugar bloom. Sugar bloom may also occur if the scrub has been in an environment with too high humidity.
How to avoid sugar bloom?
The best way to avoid sugar bloom is to avoid condensation by storing your scrub in an area of low humidity and stable temperature.
IMPORTANT: Blooming is not mold nor fungus.
FAT BLOOM, unlike sugar bloom, is not always caused by a simple set of circumstances, such as the scrub 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 scrub. As the name implies, the bloom is composed of fat, in this case cocoa butter.
When discussing the reasons for fat bloom, it is important to note that when cocoa butter hardens, it forms crystals. Some types of cocoa butter crystals are stable, but other types of the crystals are not and will actually change their form over time. First crystals that form are the unstable ones, which will slowly change their forms to more stable ones. When this transition occurs, the scrub contracts (shrinks in size). The new stable crystals project above the surface of the scrub, visible as bloom.
If the scrub is stored in an environment, where the temperature fluctuates near the melting temperature of the stable crystals, fat bloom may form. Some of the crystals melt, and when they recrystallize, they recrystallize slowly, since the ambient temperature is close to that of the cocoa butter. This allows the crystals to grow much larger than the original small, compact crystals. In addition to projecting above the surface of the scrub, these larger crystals may displace cocoa butter, forcing it to the surface. Hence the white spots.
How to avoid fat bloom?
Because the most common cause of fat bloom is temperature fluctuation, avoiding those fluctuations will minimize occuranc of fat bloom. If the product is stored in ir conditioned room, outlet might me too close to the product or it may simply be undersized for the room to be cooled.
A Simple Test to determine type of blooming
One way you can easily check to see if a scrub has undergone sugar bloom or fat bloom is to touch the scrub with a drop of water. If the dusty appearance disappears, then it is sugar bloom. If the bloom remains, then it is fat bloom.