Eight interesting facts about pho: (picked and translated from source)
1. During 1908-1909, steam boats were a popular means of transportation from Hanoi to other cities in the North, and pho started out as a vendor food sold in numbers at river ports. From 1930, pho was popular in the cities, some pho restaurant in Hanoi served until 4 AM.
2. Originally there was only pho with well-done beef. Rare beef was a latter innovation, and only became dominant after 1954.
3. Within the first decade when pho was popular, many cooks tried to add different twists and turns to the dish, however, not all could satisfy the public taste. A few variations that we don’t see today are pho in the Jean de Puis neighborhood (Hang Chieu, Hanoi) with sesame oil and tofu (1928), pho gio (rolls of sliced beef), pho Phu Doan with ca cuong extract(*).
4. Chicken pho first appeared in 1939, when beef was not sold on Wednesday and Friday, and there was no fridge.
5. Pho sot vang is a nice mix of Vietnamese and French cuisine: the chunks (not slices) of beef are seasoned and stewed in wine (vang), then added atop the pho. (This is the first time I’ve heard of this type of pho)
6. Pho did not migrate to the South until 1954 – when the Geneva treaty was signed and Northerners migrated to the South to escape the rule of Communists. This is the historical mark of pho spreading all over the country.
7. Southern pho, easy-going and generous like the Southern Vietnamese, have add-ons that its Northern brother didn’t think of: bean sprouts, fresh herbs, a little sugar in the broth, hoisin sauce and hot sauce.(**)
8. A few famous Pho restaurants in Vietnam (that I’ve seen in Houston and California, but I’m not sure if they are the real deal): pho Tàu Bay (“airplane”) (Hanoi, 1950)(***), pho Thìn (Hanoi, 1955), pho Hòa-Pasteur (Saigon, 1960).
* I had this extract once in a bowl of bun moc, just a drop, literally, and it’s so strong it killed the broth and my appetite. The only other time I had something to that effect was when I dunked sushi in wasabi.
** Pho shacks in the North still hesitate to serve all these condiments today, which in my opinion is quite understandable. The veggies only clutter the soup and get you full more quickly. The sauces only overpower the natural broth (which already has at least a dozen different ingredients), and distract you from the real taste of pho.
*** The first owner of pho Tau Bay did not name it so. A friend gave him a pilot helmet, which he really liked and wore often. Customers then started calling him “ong tau bay” (Mr. Airplane) (?!) and the name stuck.