I have recently gotten into making my own soft drinks, and I would like to attempt making a cola.   I found an online spice retailer that sells Kola Nut and bought some, but I have no real idea how to prepare them for use.   I also don't know how much I should use for a liter or two of soda, but I can figure that out via experimentation if I have to.  But what should I do with the kola nuts?   Do they need to be ground before I boil them in a simple syrup, or should the pieces just be dropped in as-is?   How much time does it take to extract the flavor from them?  Edit:  I have made my own ginger ale using fresh ginger and my own berry soda using a bag of frozen berries, and I am a homebrewer and have a kegging system and a carbonator cap for soda bottles.   I really just want to know if there are special considerations for how to treat kola nuts. 
Full disclosure — I'm not Vietnamese :-)  The word "pho" (actually "Phở") is a corruption of the French word "feu", as in "Pot au Feu", the dish that it can claim as its ancestor. (That's from a Smithsonian Magazine article about Vietnamese food from sometime in the past few years.)  It's a stock-based brothy soup, usually with at least onions and rice noodles and often (by customer choice) one or more meat additions.  Sometimes the meat is added raw to the boiling hot soup immediately before serving. The dish is almost always served with a side platter of fresh herbs, bean sprouts, sliced-up chiles, and lime.  The herbs are usually something like mint, Thai basil, and cilantro (or equivalent).  It's not a super-fancy dish, and to my knowledge there's no International Phở Licensing Board, so the rules as to what is and isn't "correct" are probably pretty loose. I've had an awesome veggie-broth Phở, for example. 