Heston Blumenthal introduces his recipe for the most perfect bangers and mash. Delicious recipe with a scientific flair from the Michelin star winning chef's BBC cookery show 'In Search of Perfection'. In part one, see how the chemistry chef applies his knowledge of temperatures to make the perfect raw sausage. Watch more high quality videos on the Food YouTube channel from BBC Worldwide here: http://www.youtube.com/bbcfood