Dry toasting
Heating whole spices in a dry pan until fragrant, to deepen flavour before grinding.
Also: dry roasting, dry-roasting spices, bhunna, pan toasting
Dry toasting means warming whole spices in a heavy pan without oil, shaking or stirring until they darken slightly and smell strongly, usually one to three minutes. Heat drives off surface moisture, which makes the spices brittle and easier to grind, and it triggers browning reactions and releases volatile oils. Cumin, coriander, fennel, mustard, fenugreek and chillies are all commonly toasted. Spices should be removed from the pan the moment they smell strong and cooled on a plate, since carryover heat can scorch them, and burnt spice turns bitter. Delicate spices such as cardamom and saffron need gentler treatment. Use medium-low heat.