Hot sauce can inspire fervent passion in its devotees. It’s a global obsession that translates to billions of dollars of sales a year. But with so many on the market, how do you create a taste that becomes a global hit? In this programme, Ruth Alexander explores the origin stories of two iconic brands – Sriracha and Lao Gan Ma. How did these sauces - born in humble circumstances in Vietnam and China in the 1980s - come to sit on dining tables around the world today? We explore their extraordinary stories and ask what their popularity tell us about changing global tastes. If you would like to get in touch with the show, please email: thefoodchain@bbc.co.uk (Picture: Large red chilli. Credit: Getty/BBC) Producer: Sarah Stolarz Contributors Stephanie Li, blogger and YouTuber at ‘Chinese Cooking Demystified’ Andrea Nguyen, cookbook author and publisher of Vietworldkitchen.com