Salt

Steph McGovern sets out to explain this role.

She hears how it has taken root in our language, visits a chemistry class to find out about how it's produced and its importance to our physical well being, talks with history professor Peter Wallenstein about the unexpected importance of salt in military strategy right up until the 20th Century.

Pierre Laszlo explains how salt not only helped shape economies and cities like Salzburg, Munich and Venice, but also played a crucial role in revolutions across France, America and India.

Steph also visits a graveyard and hears talk of the tradition of sin-eating at Welsh wakes, an illustration of salt's widespread place in religion and superstition across the world.

Finally she talks with a commodities expert to discover just how much salt is worth today - significantly less than the days it was traded like for like with gold.

Steph McGovern explores the rich, perhaps unexpectedly diverse history of salt.

It's easy to take salt for granted - its abundance on supermarket shelves, coupled with the development of refrigeration and freezing for our food, means we can all too readily overlook its vital and multiple role in our history.

She hears how it has taken root in our language, visits a chemistry class to find out about how it's produced and its importance to our physical well being, talks with history professor Peter Wallenstein about the unexpected importance of salt in military strategy right up until the 20th Century.

Steph also visits a graveyard and hears talk of the tradition of sin-eating at Welsh wakes, an illustration of salt's widespread place in religion and superstition across the world.

In the conclusion of her two-part investigation, she begins in Anglesey at the Halen Mon sea salt company, learning how they produce their salt from the waters of the Menai Straits. Then Steph moves on to learn more about the wide variety of artisan salts that have become so popular in recent years - from French Fleur du Sel to the beautiful pink Himalayan Rock Salt.

Steph goes on to address the issue of salt and health, hearing from a campaign group promoting the lowering of salt consumption down to 6 grams a day through schemes such as reducing the number of holes in chip shop salt shakers.

Finally Steph heads down the salt mine at Winsford in Cheshire, with 160 miles of tunnels and an off-shoot storage facility that capitalises on the ideal humidity by storing everything from grand pianos and barrel organs to unwanted waxworks.

Steph McGovern continues her exploration of one of life's essential ingredients - salt.