There are two main types of ganache: pastry ganache and confectionery ganache. How a chef combines ganache ingredients and in what ratios depends on how they intend to use it. Will it fill a molded bonbon? Will it be layered with pate de fruit and enrobed? Are they filling or icing a cake?

Pastry ganache, used in cakes, ice creams, and plated desserts, can be as simple as one part cream to one part chocolate with small adjustments to alter the ganache's firmness. It does not need a long shelf life; generally, a chef will need a silky smooth texture and great flavor—nothing more complicated. 

Confectionery ganaches have a much heavier burden placed upon them! The ganache's purpose is one factor chefs consider when determining their recipe. A ganache created to fill a molded bonbon can be quite soft, even liquid, while a framed filling meant to be cut and enrobed must have a more solid texture. In addition, many confectioners (though not all) are concerned with shelf life issues. This, too, will affect what ingredients they use and the ratios in which they use them.