Sarah is the founder of Wonderbag; a simple but revolutionary non-electric heat-retention cooker. It continues to cook food that has been brought to the boil by conventional methods for up to 12 hours without the use of additional fuel. The Wonderbag also keeps food and beverages cold; "Freeze it, bag it, store it, serve it". Sarah has recently passed the one million mark for Wonderbags sold!  In this episode, she shares the story of how she started the Wonderbag, along with lessons she's learnt from her experience as an entrepreneur.