The structure of ganache. Left: Soft ganache is made with an equal proportion of chocolate and cream, with cocoa particles and droplets of cocoa and milk fat surrounded by a syrup of the chocolate’s sugar and the cream’s water. Center: A firm ganache, made with more chocolate than cream, contains proportionally more dry cocoa particles and less water. Right: With time, the cocoa particles in a firm ganache absorb water from the syrup and swell. This can crowd the fat droplets so tightly that they coalesce and the ganache separates.