Jimmy Doherty asks what makes a London dry gin a London dry gin. He also finds out about a threat to British juniper berries that could spell the end of gin's recent resurgence. Kate Quilton heads to tropical Hawaii to find out why macadamia nuts aren't sold in their shells. She ropes in some Hawaiian muscle in the Big Island shipyards to help crack the case. At a Food Unwrapped party, Matt Tebbutt grosses out the crew with his notorious habit of double dipping: going back for a second dip in a communal salsa with a tortilla chip that's already been in his mouth. In a laboratory, Matt investigates what germs he may be transferring to the dips, and whether he needs to change his mucky ways.