The smoke point of oil is crucial for tadka because using an oil with a low smoke point can result in a burnt, bitter flavor, while using an oil with a high smoke point allows the spices to bloom properly without burning.
Tadka, also known as tempering, involves heating oil or ghee and then adding spices to it. The hot oil infuses the spices, releasing their aroma and flavor. The smoke point of an oil is the temperature at which it begins to break down and produce visible smoke. If the oil's smoke point is too low and it's heated beyond that point, it will not only produce an acrid, unpleasant smell and taste, but it can also release harmful compounds. For tadka, you want an oil that can withstand the heat needed to properly bloom the spices without reaching its smoke point. Oils with higher smoke points, like refined vegetable oil, canola oil, or ghee, are generally preferred for tadka because they can handle higher temperatures without burning. This allows the spices to release their flavors fully, resulting in a more flavorful and aromatic tadka. Using an oil with a lower smoke point, such as extra virgin olive oil, may cause the spices to burn quickly, imparting a bitter taste to the dish.
Always heat the oil gently and watch it carefully. If you see smoke, immediately remove the pan from the heat to prevent the spices from burning and developing a bitter taste.