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What is a Chocolate Bloom?

G. Wiesen
G. Wiesen

Chocolate bloom refers to the formation of crystals on the exterior of chocolate which makes the surface appear gray, swirled, or gritty. This typically occurs due to poor or improper storage, or as part of preparing chocolate for use in making candy without properly tempering the chocolate. There are two basic types of blooming that can occur in chocolate: fat blooming occurs when the fat solids in cocoa butter melt and come to the exterior of the chocolate, before reforming as crystals; sugar blooming occurs when sugars crystallize on the chocolate exterior. Chocolate bloom results in an unpleasant appearance and potentially a gritty texture, but does not alter the taste of the chocolate. Bloomed chocolate can still be safely consumed.

Though there are two basic ways in which chocolate bloom can occur, they both tend to create similar results. The surface of the chocolate will often appear gray or swirled, and it may also take on a gritty appearance and texture. Both types of chocolate bloom often occur due to improper storage or handling of chocolate, usually resulting in exposure to moisture or extreme changes in temperature.


Fat blooming is one of the major causes of chocolate bloom and often produces the gray exterior commonly perceived as a bloom. There are a few different theories as to why this type of blooming occurs, but it is attributed to the fats in cocoa butter used to produce chocolate. The interior fats typically melt or separate from the rest of the chocolate, and emerge through pores to the exterior of the chocolate. Once at the outside, these fats solidify once more and create a gray coloration.

The fat solids in cocoa butter melt to cause fat blooming in chocolate.
The fat solids in cocoa butter melt to cause fat blooming in chocolate.

Sugar blooming is the other major cause of chocolate bloom and produces a gritty texture and appearance. This type of blooming occurs when sugars in the chocolate, often on the exterior, are exposed to water or moisture and dissolve. Once the moisture evaporates, the sugars are left behind and form crystals. This creates an appearance and texture that is gritty, since the sugar crystals coat the exterior of the chocolate.

Chocolate bloom does not typically affect the flavor of the chocolate, and it can be eaten safely, though it may be unsightly. Melting chocolate that has bloomed will often remove the discoloration or gritty texture, though it should be tempered before returning to a solid form to prevent future chocolate bloom. Tempering involves a process of alternately heating and cooling chocolate to control how the fats in the cocoa butter behave, preventing fat blooming. As long as the chocolate is tempered and not exposed to moisture or high humidity, blooming should not occur.

Discussion Comments


A few years ago, I went on a short trip to a factory, where I was shown how chocolate was made. One thing I learned while there was about chocolate, fat and sugar blooming. It was definitely an interesting process. Although the chocolate didn't seem all that difficult to make, I could tell that it was much more of a process than many other candies that are produced. One example is how the factory and chocolate vats have to be kept at a certain temperature, in order to ensure stabilization.


Even though I enjoy chocolate quite a bit, one of the main problems I have with it is that it's not one of the more stable candies. Not only can sugar bloom effect its appearance greatly, but even more so, failure to package it right can also lead to issues, especially depending on the weather.

For example, in the wintertime, if someone was to order chocolate online, they wouldn't have to worry about how stable it would remain if it were to get shipped out, since the cold weather would protect it from harm.

However, if that was the summer, it's a completely different story. Since it melts very easily, it would more than likely have to be shipped in dry ice, and even then, you might run into some trouble. Overall, chocolate is one of those things that you either love or hate.


I have never heard of the term "chocolate bloom" before, and this is a very interesting article. In my opinion, it really shows how no matter what kind of product you're making, it has to remain stable or properly stored. Failure to do so can obviously lead to things such as this. Also, on another note, even though bloomed chocolate can be eaten safely, I wonder if the appearance will affect how people perceive its taste. For example, some brands of food can have the exact same taste, but because we "eat" with our eyes as well, we might end up getting deceived. After all, one of the most important things of any product is visual presentation.

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    • The fat solids in cocoa butter melt to cause fat blooming in chocolate.
      By: svl861
      The fat solids in cocoa butter melt to cause fat blooming in chocolate.