The difference between raw and roasted hazelnuts is not just colour. Roasting is a controlled transformation in which hundreds of aroma compounds are born, texture turns crisp and the skin releases. The mechanism driving it is the Maillard reaction between sugars and amino acids.
The dance of temperature and time
Industrial roasting typically runs at 120–160°C for 15 to 40 minutes depending on the target profile. Low and slow gives homogeneous colour and a soft aroma. Hot and fast produces intense roasted notes but leaves a narrow tolerance — a few minutes' deviation tips into bitterness.
The colour scale — light golden, medium, dark — is the standard language of customer specifications. Chocolate makers mostly ask for medium profiles; the snack market prefers darker, more assertive roasts.
The role of quality control
Roasting is also a food safety step: the heat treatment reduces microbial load and brings moisture to its final band. At Koralla, no batch ships without passing colour measurement, moisture analysis and a sensory panel. If the birth of aroma is chemistry, its consistency is engineering.
