Ever wondered why your grandmother threw a teabag into the pressure cooker while boiling chickpeas, or why she measured using the knuckle of her index finger? Why does a counter-intuitive pinch of salt make your kheer more intensely flavourful? What is the Maillard reaction, and what does it have to do with fenugreek? What does your high-school chemistry knowledge, or what you remember of it, have to do with perfectly browning your onions? Just like memorizing an equation might have helped you pass an exam but not become a chemist, following a recipe without knowing its rationale can be a sub-optimal way of learning how to cook.