Tempering Chocolate

Chocolate is essentially a suspension of cocoa solids and sugar within cocoa butter fat. Cocoa butter is polymorphic, meaning its fat molecules can arrange themselves into six distinct crystalline structures (Forms I through VI) as it cools and solidifies.

Only one of these crystalline structures—Form V—is desirable for chocolate-making. Form V crystals give chocolate its trademark glossy finish, prevent it from melting immediately on your fingers, and provide that sharp, satisfying 'snap' when broken. Un-tempered chocolate sets into a mix of unstable crystals, resulting in a dull, crumbly texture with white streaks of 'bloomed' fat on the surface.

To achieve pure Form V crystallization, chocolatiers use precision temperature curves. First, the chocolate is heated to around 115°F (46°C) to completely melt all existing fat crystals.

Next, it is rapidly cooled to 82°F (28°C) while being agitated (often by spreading and folding it on a cool marble slab). This cooling stage encourages the formation of both Form IV and Form V crystals. Finally, the chocolate is carefully heated to exactly 88–90°F (31–32°C). This narrow temperature band is high enough to melt away the undesirable Form IV crystals, but low enough that the desirable Form V crystals remain intact to 'seed' the rest of the batch.