The act of puckering one’s lips and experiencing a tingling sensation in the jaw, once instinctively associated with detecting the presence of poisonous or spoiled foods, has evolved into essential cues, guiding us through the exploration of diverse flavours and cuisines. The sour taste, triggered by a product’s low pH, whether coming from the acids in unripe fruit, spoiled milk, or the sharpness of confections, is a fundamental feature of our five senses, evoked by a chemical reaction.