Gregg Wallace is in Leeds, at an enormous mattress factory where they produce 600 bouncy beds every day. He follows the production of pocket-sprung mattresses from the arrival of hard steel right through to soft bedding heading out of dispatch. Along the way he learns how lengths of metal are stretched into thin wire and coiled into springs which are placed into individual pockets. And how the mattresses are designed to wick sweat away from our bodies with the help of natural fibres like hemp and wool.

Meanwhile, Cherry Healey is learning whether there are benefits to be had from taking an afternoon nap. She meets up with a sleep scientist who tells her that we should be making time for a snooze rather than reaching for a cup of coffee. To prove his point, he runs an experiment which demonstrates that reaction times can be improved by a short sleep. 20 minutes is the optimum nap time - any longer risks falling in to a deep sleep which is difficult to wake from. And she is visiting a sheep farm where she sees how wool is shorn and discovers its amazing anti-bacterial and fire-retardant properties, which make it perfect for lining a mattress.

Historian Ruth Goodman is investigating the origins of the modern mattress. She lies down on a straw stuffed sack which the lower classes would have slept on in the middle ages and learns how steel transformed our bedtime habits, first with the 'innerspring' and then with the more comfortable 'pocket spring' technology. And she learns how a famous Scandinavian inspired home store is responsible for our enduring love affair with the duvet.

Gregg Wallace is in Cornwall at an enormous bakery where they produce 180,000 Cornish pasties a day. He follows the production of the pastry snacks from the arrival of two tonnes of swedes right through to dispatch. Gregg learns that there are very specific rules to creating a Cornish pasty. They 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.

Meanwhile, Cherry Healey is delving into the wonderful world of the onion. She peels back the layers to discover the science that makes it such a versatile vegetable, and more importantly, why it makes us cry. It is all down to a chemical called lachrymatory factor, which is only created when an onion is cut into. Cherry visits an anaerobic digestion plant, where they turn waste from food factories into electricity. Micro-organisms feed on food waste, producing methane gas, which is used to power generators.

Historian Ruth Goodman is debunking some common Cornish pasty myths. It has been claimed that the county's tin miners invented the pasty as a convenient snack to eat while they toiled at the rock face. She learns that miners may have eaten them, but they didn't invent them. And it is unlikely that they used the pastry crimp as a handle. She also visits the Worshipful Company of Grocers in London, which was responsible for importing pepper into Britain. She learns how this ubiquitous seasoning transformed from a commodity so valuable it was known as black gold to a spice that everyone could afford.