Caramelisation — the thermal decomposition of sugar into hundreds of flavour compounds — is simultaneously the simplest and most misunderstood technique in the pastry kitchen. Simple because the ingredient is one (sucrose) and the equipment is basic (a heavy pot and a heat source). Misunderstood because the flavour stages within what we call "caramel" are not a single flavour but a spectrum — and the finest French pastry chefs work that spectrum deliberately, stopping at different points for different applications.
Sucrose begins to melt at 160°C and begins to decompose into caramelisation products from approximately 170°C. What happens next is a cascade of chemical reactions producing over 1000 distinct volatile compounds. The flavour stages across the caramel spectrum — with the sensory cues that experienced pastry chefs use to identify each:
1. The pan does not lie — use a pale (stainless or copper) pan so colour can be read accurately. Dark pans make colour judgement impossible. 2. Do not stir a wet caramel once the sugar has dissolved — stirring causes crystallisation. Swirl the pan to distribute heat. 3. Cold cream causes violent bubbling when added to hot caramel — add slowly, in a thin stream, with the pan removed from heat. The reaction is safe but vigorous. 4. Glucose syrup added to wet caramel (10–15% of sugar weight) prevents crystallisation during and after cooking — useful for large batches and for caramels that will be stored Sensory tests: - **Colour is the primary indicator** — not time, not temperature alone. Learn the colours: pale straw, dark honey, mahogany. - **Smoke tells you before the thermometer:** A very fine wisp of smoke rising from the surface of the caramel is the first sign of approaching the dark caramel stage. Visible, significant smoke means you are at the edge of burnt. - **The smell test:** At medium caramel, the kitchen smells of butterscotch and toasted sugar simultaneously. At dark caramel, the roasted note dominates. At burnt: acrid, sharp — unmistakable. - **The cold water test:** Drop a small amount into cold water. At soft ball: a pliable mass. At hard crack: a rigid, snapping piece. At correct caramel stage: a brittle, amber-coloured shard that tastes of caramel.
French Pastry Deep: Sugar Work, Chocolate, Regional & The Untranslated Knowledge