The second episode of Michael Mosley and James Wong’s globe-trotting series about the science of our food is all about taste.

Our tongue holds around 4,000 taste buds and inside them are the five taste receptors – sweet, salty, bitter, sour and umami. In humans, this is where the taste begins.

In Spain, Michael learns why Ibérico ham is so irresistible, while in Peru, James learns how the Incas tamed the poisonous potato.