Tempering Chocolate

Tempering has been part of confectionery chocolate work since the development of conched, emulsified chocolate in the late 19th century. Before the understanding of cocoa butter polymorphism, chocolate workers achieved correct tempering through experience and tactile knowledge alone — using the cool marble slab and specific hand movements that remain the classic technique even now that the crystallography behind them is fully understood.

The controlled heating, cooling, and re-warming of chocolate to specific temperature windows that encourage only the desired cocoa butter crystal form (Form V) to develop — producing a chocolate that sets with a high gloss, a sharp snap, and a clean melt. Chocolate that has not been tempered sets soft and dull, develops fat bloom (grey, streaky surface), and lacks the textural character that makes a correctly tempered coating or confection what it is. Tempering is pure crystal chemistry applied to a kitchen material.

Correctly tempered chocolate delivers its flavour differently from untempered. Form V crystals melt at precisely 34°C — human body temperature — which means correctly tempered chocolate melts completely and rapidly on the palate, releasing its volatile aromatic compounds in a single clean release. Out-of-temper chocolate (Form VI) melts at a slightly higher temperature, meaning it lingers on the palate slightly longer and releases its aromatic compounds more slowly — the flavour is perceivably different. As Segnit notes, dark chocolate's primary flavour compounds — pyrazines from roasting, theobromine, and phenylethylamine — are all fat-soluble and are carried by the cocoa butter in solution; the correct crystal structure of tempered chocolate controls exactly how and when this solution releases on the palate. Sea salt with dark chocolate works because sodium suppresses bitter taste receptor response, moderating theobromine's bitterness while simultaneously amplifying the perception of the chocolate's fruit and roast character.