Sugar bloom

Sugar bloom is a surface defect on chocolate that appears as a rough, white, grainy coating caused by moisture dissolving the sugar on the surface, which then recrystallizes as the water evaporates. Unlike fat bloom, which is caused by cocoa butter migration, sugar bloom is triggered by exposure to humidity, condensation, or direct contact with water. The affected chocolate feels gritty to the touch and loses its smooth appearance.

The most common causes of sugar bloom include storing chocolate in humid environments, moving it from cold to warm conditions (which creates condensation), and improper packaging that allows moisture to reach the product. Prevention requires maintaining storage conditions below 50–60% relative humidity and avoiding sudden temperature changes. While sugar bloom does not make chocolate unsafe, it significantly damages the visual appeal, texture, and consumer perception of quality — making it a costly defect in commercial production.

Learn more about sugar bloom — including causes, prevention strategies, and how to distinguish it from fat bloom — in the articles below.