Briony May Williams finds out why some radishes are hot. Andi Oliver asks why pre-made sandwiches contain mayonnaise. And Kate Quilton discovers how truffles are grown.

Matt Tebbutt is in Spain learning why some oranges are so hard to peel, while Jimmy Doherty heads to Thailand to discover why coriander is the herb of choice for some, but for others it seems to taste like soap. Briony Williams finds herself in a bit of a jam as she interrogates an important kitchen conundrum - why dropped toast always lands the wrong side down

More fun facts about our food, including: why some fruits are hairier than others, the difference between single and double cream, and the science of why canned food keeps for so long.

How come schnapps is always clear even though it's made from colourful fruits? Why do supermarkets carry so many of the same herbs? Plus: soft and crusty bread rolls compared.