Bloom is a visual defect caused by the destabilization of the chocolate structure. It shows up in two forms: fat bloom, where thermal fluctuations cause cocoa butter to migrate to the surface and recrystallize as grey streaks, and sugar bloom, where exposure to moisture dissolves surface sugar, which then re-crystallizes into a gritty white layer upon drying. While aesthetically displeasing, the product remains safe for consumption, though the texture is often compromised.