Inside the Factory

The British love eating crisps. So much so that we get through a staggering half a billion crisps a day - and that takes 17 million potatoes. So why do we love the humble fried potato snack so much, and what are the secrets behind making the perfect crisp?

In the second episode of Inside The Factory, Gregg Wallace and Cherry Healey go in search of these answers and discover plenty of surprising facts along the way.

We'll see Gregg at the largest crisp factory on earth - Walkers factory in Leicester - as he follows 27 tonnes of potatoes as they are peeled, sliced and fried to make more than five million packets of crisps every 24 hours. He'll discover how each bag is filled with nitrogen to keep the crisps from going stale - and if you ever wondered how a crisp gets it flavour then we'll get to see the inside of the factory's development kitchen, where seasoning begins its crisp life as a real food dish.

Meanwhile Cherry Healey discovers the secrets of perfect crisp potatoes, and how it is all down to a potato's sugar content. She also finds out that our noses play a central role in how things taste and ambiance can be as big factor as ingredients. Plus she follows the production of Monster Munch, where the factory transforms 96 tonnes of corn into 12 million monster feet every single day.

And historian Ruth Goodman investigates who really invented the crisp: was it the Americans, as is often cited, or the British? Ruth cooks up the earliest known recipe for crisps to uncover the truth.