Thanks for the suggestion on the kits Mark. All the kits seem to have already flavored root beer extracts. I want to make my own flavors.
Your local beer brewing store with have everything you need to make it. Start using extracts and work on the spicing. Then backward integrate that into making your own extract.
I have moved from root beer to birch beer. It is a wonderful soft drink.
Bob, why do you suggest starting with extracts first? Why can't I just buy the spices and do it myself?
I've never heard of a "beer brewing store". They really exist?
I think I had birch beer once when I was a kid. I don't remember the taste though. I also tried sasparilla and liked it. I've had Stewart's ginger beer. I don't know if they still make it. It was hard to find where I lived at the time. It was pretty good.
I did a little research and apparently, you can't buy sassafras root in the U.S., which is where root beer originally got its flavor from. It has something called safrole which is a carcinogen. I've seen recipes that call for sassafras root, so I guess you have to be lucky enough to find wild sassafras and pick it yourself.

What do the commercial brands use for their flavoring?
I wonder if birch beer would be more convenient to make. Maybe I could try ginger beer or sasparilla, but I really want to make root beer.
"So Lonestar, now you see that evil will always triumph. Because good is dumb!"