My chocolate has a dusty white coating — is it safe to eat?

The dusty white coating that sometimes appears on chocolate is known as 'bloom.' It can manifest as either a fat bloom or a sugar bloom. Fat bloom occurs when the fat, such as cocoa butter, in the chocolate separates and rises to the surface. This can happen due to changes in temperature, causing the chocolate to soften and then harden again, leaving a whitish film. Sugar bloom, on the other hand, occurs when moisture causes the sugar in the chocolate to dissolve and then recrystallize on the surface, resulting in a grainy texture.

Both types of bloom are quite common and are more about aesthetics than anything else. They are usually harmless, although they can affect the texture and mouthfeel of the chocolate.

Fat bloom and sugar bloom occur due to different scientific processes. Fat bloom is the result of temperature fluctuations, where the cocoa butter within the chocolate melts and re-solidifies unevenly, leading to a dull and streaky surface. This type of bloom generally results from storing chocolate in a place where the temperature frequently changes, such as near a window or a frequently opened pantry.