Gregg Wallace visits the biggest tortilla factory in Europe. The Coventry site covers more than 21,000 square meters, the size of three football pitches, and makes 60,000 tonnes of snacks every year. Gregg is following production of their UK bestseller, the 150g sharing bag of chilli heatwave flavour tortilla chips.Meanwhile, Cherry Healey visits the UK's largest chilli farm, where her tastebuds take on the hottest chilli in the world. She also discovers the science behind the UK's first compostable crisp packet.And historian Ruth Goodman reveals the starchy story of how the Elizabethans kept their huge ruff collars standing to attention, as well as taking a trip to the flicks to discover how American popcorn became a box office smash.