Inside the Factory Episode Rating Graph

Gregg Wallace explores Ribena's Gloucestershire factory. Meanwhile, Cherry Healey is in the lab figuring out why fizzy drinks are so appealing.

How a factory in Ireland produces 540,000 bottles of liqueurs a day. From grain, to barrel aging, to mixing cream and whiskey together, the show traces the production of a cream liqueur over the span of three years. How Ireland’s bottles and jars are recycled at a plant processing 500 tonnes every day. How all alcoholic drinks - not just aperitifs - stimulate appetite. The rules for producing and labelling whiskey, bourbon, and blends. How monks invented liqueurs. The impact of modern distillation methods on traditionally made alcohols like Irish whiskey.

Gregg Wallace, Cherry Healey and Ruth Goodman look at the production, science and history of bread in Britain.

How a factory in Nottinghamshire produces 250,000 jars of curry sauce each day. How chillies are harvested on small farms in India, dried, packed down, and processed into chilli powder. How four rules for cooking rice guarantee it will come out right every time. Recreating a 1747 recipe for rabbit curry. How a British Asian housewife brought restaurant curries closer to Indian home cooking.

How a cheese factory in Gateshead produces 3,000 tonnes of spreadable cheese every year - making cheddar, chopping and blending it with whey, water, and other ingredients. How bacteria affect the aroma, flavour and appearance of cheeses. How to make perfect cheese on toast. How cheddar became the predominant hard cheese world wide. How Kraft made processed cheese 100 years ago.

How a bakery in Cornwall produces 180,000 Cornish pasties a day. There are rules: A Cornish pasty must be made in Cornwall; the filling can only contain onion, potato, swede, beef and some seasoning; and each ingredient must be cooked from raw within the pastry parcel. The versatility of onions, and how they make us cry. How anaerobic digestion turns food factory waste into electricity. Challenging the pasty's origin story. How importation of pepper eventually transformed it from a precious commodity to a spice that everyone could afford.

How a factory in Leeds produces 600 bouncy beds every day - from making steel into springs, to their placement in individual pockets and covering in natural fibres like hemp and wool designed to wick away sweat. How a short, twenty-minute sleep improves reaction times. How wool is shorn from sheep, and its inherent anti-bacterial and fire-retardant properties that make it well suited to mattresses. How the modern spring mattress evolved. How a famous Scandinavian-inspired home store is responsible for popularizing the duvet.

How a factory in Manchester produces 700,000 toilet rolls a day starting with spruce timber offcuts from Sweden, pulped and rolled onto 1.2-tonne 'mother reels'. How the water treatment works of Brighton remove debris, grease and bacteria to produce clean water in little more than an hour. How a high-tech Japanese toilet addresses hygiene. How waterless toilets could improve sanitation for one-third of the world's population. The history of the modern flush toilet.

Gregg Wallace is at the world's largest dried pasta factory in Italy, where they produce 150,000 kilometres of spaghetti each day.

Gregg Wallace explores the Grimsby factory that processes 165 tonnes of fish a week and produces 80,000 cod fish fingers every day.

How a foundry in France produces a cast iron pot every five seconds - from the arrival of 20 tonnes of crude iron right through to brightly coloured orange casserole dishes. How a South African iron ore mine - one of the largest in the world - produces a staggering 670,000 tonnes every day. The science behind cooking the perfect casserole - more cooking time isn't always better. The history of one-pot cooking to prepare simple meals, from communal ovens to 1970s slow cookers. How casting iron in sand moulds democratised the kitchen through affordable cookware.

How a factory in Italy produces 400,000 frozen pizzas each day. The science that makes mozzarella work so well on pizza. How pork is transformed into pepperoni. How freezer ships and trucks create the worldwide cold chain that enables this business to exist. How pizza was first popularised by a restaurant in London’s Soho in 1965

Gregg Wallace receives a load of corn fresh off the boat from Argentina and follows its journey through the largest breakfast cereal factory in Europe.

How the largest malt loaf factory in the world makes the sweet and squidgy cake-cum-bread, a popular teatime treat consumed at the rate of 130 million a year. How a British baking company cooked up the first business computer. How wheat flour was ground the traditional way, until the Victorians' demand for white bread brought about the demise of Britain's iconic windmills.

How a factory in Lowestoft produces 450 tonnes of frozen food each day. The differences between waxy and floury potatoes, and which you should use for which job. How the potato's nutritional value compares to other fruits and vegetables. The history of potatoes is traced to Spanish explorers and an enterprising French chemist called Parmentier, who popularised the exotic new vegetable. How Mr Whippy ice creams inspired the potato waffle, a teatime treat.

How a factory in Derbyshire produces 175,000 jars of instant coffee every day, from green coffee beans to the freeze-dried final product. How roasting alters the chemical composition of coffee. How caffeine affects the body and brain. How climate change is affecting coffee harvests worldwide, and the coffee species that could cope with warmer growing conditions. The history of instant coffee going back to the American Civil War. How passion for coffee led to the founding of the Stock Exchange, auction houses and newspapers.

Gregg Wallace, Cherry Healey and Ruth Goodman look at Britain's love of chocolate and visit one of the world's largest chocolate factories in York.

How a factory in Essex produces 400,000 cereal bars a day - from nuts to cranberries and sultanas to puffed rice, with a carefully balanced blend of honey and glucose binding it all together for the ideal texture. How macadamia nuts are harvested in South Africa, and shelled under extraordinary pressure. The scientific distinction between botanical nuts, legumes and drupes. The history of Britain's cereal bars, including one Kendal Mint Cake snack bar made popular by famous explorers Ernest Shackleton and Sir Edmund Hillary.

How a factory in Stoke-on-Trent produces 250,000 little cherry bakewell tarts every day - from what makes a shortcrust pastry 'short' to the team of 12 precisely placing the cherry on top of every one by hand. How to swerve a soggy pastry bottom when baking pies and tarts at home. How almonds are roasted and milled into almond butter ready for toast. The origin story of frangipane, the fragrant almond filling used in cherry bakewell. How the modern cherry bakewell actually descends from a mistake.

Gregg Wallace is in Germany at a historic pencil factory where they produce 600,000 writing implements a day. Cherry Healey examines the astonishing properties of graphite. Historian Ruth Goodman traces the origin of pencils to a 15th-century graphite discovery in the Borrowdale valley.

How a factory makes 432 million classic British crumpets every year from a precise combination of ingredients, using some clever chemistry to create their famous 'holey' texture. The science of making the perfect pancake batter. How another British favourite, Eccles cakes, are made in Manchester for shipment all over the world. The history of how crumpets got their rise and eventually their bubbles, and Britain's obsession with toasting baked goods.

Paddy McGuinness visits a factory that makes forty million flapjacks a year. Meanwhile, Cherry Healey learns how oats can benefit gut health, and Ruth Goodman savours the history of the Staffordshire oatcakes and golden syrup.

In this Christmas special, new presenter Paddy McGuinness and Cherry Healey visit a chocolate factory in Belgium that produces four million chocolate seashells every day. Cherry Healey is also in Belgium, learning the secrets of white chocolate production at the biggest chocolate factory in the world, and Ruth Goodman is in a city with a familiar-sounding name, Saint Niklas, exploring the European origins of Santa.

How Farrow & Ball produce up to 200,000 litres of paint and 10,000 metres of wallpaper a week in Dorset. How a key ingredient in paint-making is mined in Devon. The art of hanging wallpaper, and its history. How ships in the First World War were painted with dazzling patterns to evade German submarines.

New presenter Paddy McGuinness visits a factory in Lincoln to explore how they make 500 million packs of Quavers every year. Cherry Healey learns how Bombay Mix is made, while Ruth Goodman reveals the wartime story behind our love of cheese flavouring.

How HSL make more than 5,000 sofas every year in West Yorkshire. The science of light bulbs, to create the perfect environment to snuggle up on the sofa. How foam padding is produced. The history of the sofa. One of the world's most famous sewing machines.

How Nestle make more than eight million bars of chocolate every day in York - the UK's city of chocolate. How a cocoa plant quarantine facility in the Berkshire countryside is preventing a worldwide chocolate shortage. The bitter history of drinking chocolate.

Paddy McGuinness makes a wonderfully nostalgic trip to the Warburtons factory in his hometown of Bolton where, thirty years ago, he had a Saturday job cleaning the machines. Meanwhile, Cherry Healey discovers how waste bread is turned into beer, and historian Ruth Goodman reveals why white bread was banned during World War Two.

How Woodmansterne produces 35 million greeting cards a year in Watford - from sketching a card design, to creating an aluminium plate for printing, to guillotining the sheets into cards and the final shipping process. Creating a vegan Christmas feast. The history of the year Christmas was cancelled.

How Lush produce an astonishing 14 million bath bombs every year in Dorset. How taking a hot bath can provide some of the benefits of exercise. How a lab grows human skin for cosmetic testing. The notion that complex perfumes ward off the plague. How the living conditions of coal miners and their families were transformed by the introduction of communal showers.

How Axminster produces 46,000 square metres of carpet every year in Devon. The science behind the best ways to remove stubborn stains from carpets such as butter, milk and red wine. How the groundbreaking methods of a Devon-based carpet maker in the 18th century revolutionised intricate carpet making. The rise and fall of the hard-wearing flooring linoleum.

How JCB make as many as a hundred iconic yellow diggers every single day in Rocester, Staffordshire, requiring just 45 hours to make a digger from scratch, and consuming 650 tonnes of steel, 170,000 bolts, 5,000 litres of paint and 236 miles of wiring each week.

How Dell Ugo make 500 million stuffed pasta parcels every year in Hertfordshire. How Cromer on the Norfolk coast still use traditional fishing techniques to catch the crab for stuffed pasta. How Italian immigrants in Bedford helped to build Britain. The origins of gluten-free food.

The futuristic process by which Heck churn out up to 90,000 vegan sausages a day in Yorkshire. How Canadian soy beans are transformed into protein-packed tofu. How a vegan superfood of the sea is harvested on the Scottish coast. The history of the vegetarian movement in Britain, and the high price that British sailors paid when deprived of their five a day.

How a Leicester factory makes one and a half million socks annually. What causes smelly feet, and which socks tackle it best. How a cotton spinner in Manchester produces 4,200 miles of yarn every hour. A revolutionary eco-cotton supplier. The history of 1980s sock fashion, and how the 'Kitchener stitch' helped save the feet of British soldiers in the trenches during the Great War.

How one million pots of yoghurt are produced every 24 hours in rural Somerset - from the Friesian cows that provide the milk to the processing, culturing, and packing processes. How blackcurrant are harvested. Plant-based alternatives to milk. Food-safe yoghurt pots made from 100% recycled material. The history of the electric milk float and the contentious origins of the cream tea.

How the biggest tortilla factory in Europe makes 60,000 tonnes of snacks every year in Coventry, including their UK bestseller: chilli heatwave flavour tortilla chips. Tasting the hottest chilli in the world at the UK's largest chilli farm. The science behind the UK's first compostable crisp packet. How the Elizabethans kept their huge ruff collars standing to attention, and how American popcorn became a box office smash.

How Denby - potterymaker since 1809 - produces one of their best sellers, the Halo Heritage mug, in Derbyshire. The journey starts at the factory's 100-metre-long, 100,000-tonne mound of clay.

How a family-run factory in rural Aberdeenshire churns out fifty thousand litres of dairy ice cream every day. How best to stop 'brain freeze.' How sprinkles are made. How ice cream vans made soft whip a favourite on Britain's streets.

How Aunt Bessie's produce a staggering 500 million Yorkshire puddings every year in Hull. How wheat is tested before it can be milled into flour. How to cook the perfect gravy for a Sunday roast. The history of the roast dinner, and the art of washing up Tudor-style.