Matt Tebbutt unbottles the mystery of wine sulphites and hangovers, Amanda Byram explores how peas could solve the plastic pollution problem, and Andi Oliver wonders how shop-bought grated cheese doesn't stick together.

The gang find out what exactly locust bean gum is. Also, why is strawberry juice so elusive at the supermarket? And in the Orkney Islands, Matt uncovers some very special residents.