Sommeliers are to a restaurant’s wine what a head chef is to its food. These waiters taste and study thousands of bottles, and the best can even tell you exactly where a wine was grown and when its grapes were harvested, just with a sniff and a slurp. But to some they can seem part of a stuffy, exclusive and mysterious club. We meet three sommeliers from the USA, Sweden and London who are all trying to change that image and guide even the most clueless of customers through their wine lists. We hear how much wine they actually drink, how they deal with know-it-all customers and a master sommelier tells us how he passed one of the most difficult exams in the world. Plus, we put all of them to the ultimate blind taste test. (Picture: Cameron Dewar, Fernando Beteta and Emma Ziemann. Credit: Cameron Dewar, Fernando Beteta, Emma Ziemann, BBC)