Surface Caramelization

Surface caramelisation describes the browning and flavour development that occurs when sugars on a food’s surface are heated sufficiently to undergo caramelisation. It can contribute golden to deep-brown colour and flavours described as sweet, nutty, toffee-like or bitter when overdone. In many cooked foods, caramelisation occurs alongside Maillard browning, so the two reactions may contribute to the same crust.

How caramelisation occurs

Caramelisation is the thermal decomposition and transformation of sugars at elevated temperatures. The required temperature depends on the type of sugar, moisture, acidity and cooking conditions. As water evaporates from a surface, its temperature can rise and allow browning to develop. Excessive heat can produce burnt and bitter flavours.

Examples in the kitchen

• Crème brûlée: sugar is heated with a torch or under a grill until it forms a brittle caramelised crust.
• Glazed carrots: sugars in the vegetable and added glaze can brown during cooking.
• Roasted squash: natural sugars may contribute caramel-like notes on browned surfaces.
• Caramelised onions: prolonged cooking develops sweet, savoury and browned flavours through several reactions, including caramelisation and Maillard chemistry.

Caramelisation versus the Maillard reaction

Caramelisation involves sugars reacting under heat and does not require proteins. The Maillard reaction involves reducing sugars reacting with amino compounds such as amino acids and proteins. Both can occur together during roasting, searing and baking.

Chef’s tip: control heat and moisture to develop colour without burning the surface. Do not assume all browning is caramelisation; protein-rich foods often brown substantially through Maillard reactions.