Gregg Wallace explores a North Yorkshire factory that produces 625,000 sausages a day. He dons stainless steel armour to join 28 Durham butchers who prepare 2,500 pork shoulders each day and follows 20 tonnes of pork as it arrives at the sausage factory. It's a short recipe - these 97% pork premium bangers require only pork shoulder meat and seasoning. He mixes up a 150 kg batch of minced meat, loads 280 metres of skin and feeds it all into a machine which can fill 600 sausages in a minute. He also tries his hand on an old fashioned piston filler, making sausages by hand. Even the most experienced hand can only produce 1,500 sausages in an hour, while the machine filler can work 2,400% faster.Cherry Healey is at the University of Chester getting the scientific lowdown on getting the best from your banger. It turns out that low and slow shallow frying delivers the best combination of flavour, moistness and succulence. But at a time when one in four people are reducing the amount of meat they eat, she heads to Middlesbrough to find out how veggie protein is created from a tiny speck of natural fungus. She also travels to Lincolnshire to find out how a 'meat sock' is the secret to wrapping a Scotch Egg every three seconds.Historian Ruth Goodman finds out how German bratwurst became a top dog in America, learning how German immigrant Charles Feltman originated the hot dog. She heads to St Albans to cook up a 2,000-year-old recipe for sausages. And finally she discovers what the Romans did for Britain by importing pepper, bay leaves and other spices that spike the modern sausages.