Malt loaf has been a popular teatime treat for more than 80 years; these days we get through a staggering 130 million of them every year. So to get to grips with how this sweet and squidgy cake-cum-bread is made, Gregg Wallace is rolling up his sleeves to get stuck in, following a production line of massive dough mixing, mind-boggling tin filling and intensely hot baking.Meanwhile, historian Ruth Goodman reveals the surprising story of a British baking company that cooked up the first business computer, as well as visiting Cambridgeshire to find out how wheat flour was ground the traditional way, until the Victorians' demand for white bread brought about the demise of Britain's iconic windmills.