Britannica Sources used in this answer

Why can yeast cause chocolate cream candies to burst?

Created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.

Learn about food preservation and the various methods to preserve foodstuffs — food preservation An overview of food preservation.

Yeast can cause chocolate cream candies to burst due to the process of fermentation. When yeast—a type of single-celled fungus—contaminates the sugary filling of a candy, it consumes the available sugars for energy.12

As the yeast metabolizes these sugars, it produces ethanol and carbon dioxide gas as byproducts. Because the chocolate shell acts as a sealed container, the accumulation of carbon dioxide gas increases the internal pressure within the candy. If enough gas is generated, the pressure eventually exceeds the structural integrity of the chocolate coating, causing the candy to crack or burst.12