Ganache is a stable emulsion of chocolate and cream (and optionally butter) whose texture, flavor, and application vary dramatically based on the ratio of these two components. The fundamental science is this: cocoa butter forms the continuous fat phase, cream provides the aqueous phase, and the cocoa solids' lecithin acts as the emulsifier binding the two. For a pourable glaze ganache, the ratio is 1:1 dark chocolate (60-65% cacao) to cream by weight. For a truffle or piping ganache, 2:1 chocolate to cream. For a soft filling, 1:1.5 chocolate to cream. The cream — 35% fat minimum — is heated to 85°C (185°F), not boiled, and poured over finely chopped or pistole chocolate in three additions. After each addition, stir from the center outward in tight concentric circles using a spatula or immersion blender, maintaining the emulsion's integrity. This technique prevents the incorporation of air that would create an unstable mousse-like texture. The center of the ganache should appear glossy and elastic — this sheen indicates a successful emulsion. If the ganache appears dull, matte, or grainy, the emulsion has broken: the fat has separated from the aqueous phase. To rescue, add a small splash (15-20 ml) of warm cream to the center and stir outward again to re-emulsify. Temperature is critical throughout: the working temperature for ganache is 32-35°C (90-95°F) for pouring, 25-28°C (77-82°F) for piping, and 20-22°C (68-72°F) for scooping truffles. Optional butter (10% of total weight) is stirred in at 35-40°C to add sheen and a smoother mouthfeel. Invert sugar (glucose or trimoline) at 5-10% of cream weight extends shelf life by binding free water and inhibiting sugar crystallization.
Pour hot cream over chocolate in three stages, stirring from center outward to build the emulsion gradually; maintain a glossy, elastic appearance at the center — dullness signals a broken emulsion; ratio determines texture: 2:1 for firm truffles, 1:1 for glaze, 1:1.5 for soft fillings; never incorporate air — stir, do not whisk; add butter and glucose at 35-40°C after the primary emulsion is stable.
For an ultra-smooth finish, use an immersion blender at a slight angle to emulsify without incorporating air — the result is noticeably superior to hand-stirring; infuse cream with tea, spices, or citrus zest at 70°C for 20 minutes before straining and using for flavored ganaches; for shelf-stable bonbons, replace 10% of cream weight with glucose and add 2% sorbitol to further reduce water activity; allow ganache to crystallize at 17-18°C (63-64°F) for 12-24 hours for optimal truffle texture before scooping and enrobing.
Pouring all the cream at once and stirring vigorously, which overwhelms the emulsification capacity and incorporates air; using chocolate below 60% cacao for dark ganache without adjusting the ratio, resulting in a ganache that is too sweet and too soft; boiling the cream, which scorches milk proteins and introduces off-flavors; using cream with less than 35% fat, providing insufficient fat for a stable emulsion; not allowing ganache to crystallize at room temperature for 12-24 hours before use, resulting in poor texture.
Chocolat (Bernachon); The Art of the Chocolatier (Notter); Professional Pastry Chef (Friberg); Chocolate: Science and Technology (Beckett)