Gregg Wallace visits a factory with a menthol scent - the Polos factory in York, which produces 32 million mints every day and contributes to the 19,000 tonnes of mints per year that the UK consumes.

Meanwhile, Cherry Healey visits the largest sugar beet factory in Europe and helps to bring in the harvest on one of the last surviving peppermint farms in the UK. And Ruth Goodman explores the clever marketing that persuaded many people to purchase minty mouthwash.