Gregg Wallace is in Derbyshire at an enormous coffee factory where they produce 175,000 jars of instant coffee every day. He follows the production of freeze-dried instant coffee, from the arrival of 27 tonnes of Brazilian green coffee beans right through to dispatch. Along the way he chills out in a freezer cooled to -46 degrees Celsius and discovers how they give you that hit of freshly brewed coffee smell when you pierce the foil lid. They extract the aroma and put it back in just before the instant coffee granules head into the jars.

Meanwhile, Cherry Healey learns about the chemistry of coffee. She finds that roasting alters its chemical composition, and listens for the 'first crack' as steam splits the bean along its seam. She also goes cold turkey on caffeine, giving up her coffee habit for five days to understand how this most commonly used psychoactive drug affects her body and brain. She discovers that the caffeine withdrawal headache is due to increased blood flow to the brain. And she is at Kew Gardens, where they have concerning evidence revealing that climate change is affecting coffee harvests worldwide. Cherry samples a brew made from the beans of a coffee species that could cope in these warmer growing conditions, and which could ensure a future for the daily cuppa.

Historian Ruth Goodman investigates the origins of instant coffee. She tastes a version that looks very like axle grease which was drunk during the American Civil War in the 1860s, and finds out why it began being referred to as 'a cup of Joe'. She also visits the site of the UK's very first coffee house, which sprang up in a London churchyard in 1652, and learns that the early passion for coffee led to the founding of modern institutions, including the Stock Exchange, auction houses and newspapers.

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.