In the early era of the ‘Colombian Exchange’ when trading ships arrived looking for black pepper they were not allowed to travel up the Red River to trade at Hanoi (Thang Long citadel), they had to deal with the Emperor in Hue city. So, the migration of spicy chili happened overland and spread northward along with other spices. Coming south were new flavours from China and so the hot sauce that northern Vietnam has developed is milder and savoury. The food they used it on was much more seasonal because of the continental climate and smoked food was much more prevalent. The French had a further impact on the taste of the north when they set up their colonial headquarters there from the 19th century. Hanoi Heat combines all these complex flavours into a smooth and truly delicious chili sauce that you can put on nearly any food you can think of.