Historically, there were a mother and her son, named ‘Thongpra’sri’ and ‘Ploikaew’. One day, they escaped from war and they stop at somewhere. At that time his mother only bring some stiff cooked rice and his mother give it to him. But, Ploikaew said“Mom, where is Kaeng? (Kaeng is a kind of soup. Kaeng and Tom Yum are not too different because it has same main components, such as lemon grass, leech lime, lime and chili). How could I eat this rice, it is so hard for me to swallow. Because these cooked rice are stiff.” Thongpra’sri respond her son “How can I bring Kaeng, because we don’t have too much time to escape. We run so fast and mom jus bring these cooked rice and dried fish”. Her son said again, “How could we eat stiff cooked rice with the dried fish.”
From this event we could know that kaeng has been made for a long-long time ago. Basically, Tom Yum is a combination of “kaeng” and “Tom Yum nam sai” and nowadays become “Tom Yum nam chon”. These three kinds of soup are still favorite nowsday. Tom Yum nam sai and Tom Yum nam khon is not really difference because it just difference from one ingredient. The ingredient is coconut/milk. For Tom Yum Nam Sai we don’t use coconut or milk but for Tom Yum nam khon, we add coconut or milk in the Tom Yum