Asked by: Anonymous
Taste is a complicated business. It used to be thought that there were separate receptor cells on different parts of your tongue for each of the five basic tastes: salt, sweet, sour, bitter and umami (the taste of glutamic acid). But more recent research has shown that individual cells actually respond to several tastes each, at different levels of sensitivity. The upshot of this is that all the tastes interact with each other – sometimes enhancing, sometimes suppressing – depending on the concentrations. So for example, at low concentrations, sour tastes will enhance bitter ones, but at moderate concentrations, they will suppress them. Which is why we put lime in a margarita.
Salt is used as a universal flavour improver because at low concentrations it will reduce bitterness, but increase sweet, sour and umami, which is desirable for sweet recipes. But at higher concentrations it suppresses sweetness and enhances umami, which is good for savoury things. It’s also easily obtained in a pure form without any interfering flavours.
Subscribe to BBC Focus magazine for fascinating new Q&As every month and follow @sciencefocusQA on Twitter for your daily dose of fun science facts.