Skipping the roasting step in a garam masala recipe will result in a less intense, less complex flavor profile, as roasting develops the aromatic oils and deepens the spices' taste.
Roasting spices before grinding them into garam masala is a crucial step for several reasons. First, the heat helps to release the essential oils within the spices, intensifying their aroma and flavor. This process, known as blooming, unlocks the full potential of each spice. Second, roasting dries out the spices, making them easier to grind into a fine powder. Finally, the Maillard reaction, a chemical reaction between amino acids and reducing sugars that occurs at high temperatures, contributes to a deeper, more complex flavor profile. Without roasting, the garam masala will taste flatter, less fragrant, and lack the characteristic warmth and depth that defines a good blend. The spices will also be more difficult to grind evenly. The final product will be noticeably different and less flavorful than a properly roasted blend.
Be careful not to burn the spices while roasting! Roast them over low to medium heat, stirring frequently, until they become fragrant and slightly darker in color. Burnt spices will impart a bitter taste to your garam masala.