The Science of Tadka: An Essential Technique for Blooming Spices

There are many ways to coax the flavor out of dried spices, but in India, they’re often bloomed in hot fat. That technique produces an infused oil called tadka, also known as chaunk (chhonk), baghaar, and many other names. The word tadka is used both to refer to the cooking method and the spiced liquid fat.

Though many cooking techniques evolved out of necessity and practicality, I’m fascinated by the science behind them, which often proves why they work. It’s what led me to write my forthcoming book, The Flavor Equation: The Science of Great Cooking Explained, out this October. With many spices (and even herbs), the aromatic molecules responsible for flavor are highly volatile. Drying spices “freezes” these flavor molecules in place (to a certain extent, and for a limited amount of time), and increases their shelf life. But drying also reduces the strength of their aroma and taste. Cooks across the globe have developed numerous ways to “unfreeze” them, or to draw them out and amplify them.

Applying heat to most dried spices—a technique known as tempering—helps move these fragrances out of the spices, so that when they hit your tongue, they produce a stronger flavor experience. (We will get into this in a bit more detail later.) Heat can also transform some of the flavor molecules in spices into new, tastier ones—or it may reduce their harshness. (It also kicks out any moisture that might have accumulated over time during storage.) The end result is an amplified sensorial experience that would not otherwise be achieved in the absence of heat. Some cooks dry-toast spices; others pound whole spices with wet ingredients before warming them. But I’m most interested in tadka, so I looked into the physical and chemical reactions that occur when dried spices are tempered in hot oil.