I tasted root beer for the first time I moved to the US. It was some store bought commercial root beer. I didn't like it much. Then I tasted fermented home made root beer and fell in love with it! The best part of it is that it is probiotic too due to the fermentation process!
I have tried two recipes for home made root beer. The one in this post I have learnt from a local culturing club (Culture Club 101) and the other I have used is from Nourished Kitchen. The main difference is the herbs used. You can use just a few different herbs, root and bark or several different kinds for a more complex flavor. It depends a lot on how many different kinds of herbs you want to buy. You can also play around with different sweeteners like maple syrup, sucanat or cane sugar. I would recommend though to use organic ingredients so the pesticides don't interfere with the fermentation process.
Home made Lacto-fermented Rootbeer
1 gallon of filtered water
2 tbsp wintergreen
2 tbsp sassafras bark
2 tbsp sarsaparilla root
1/2 vanilla bean cut in half
1 cup maple syrup, sucanat or cane sugar (I used maple syrup)
1 cup (or more if you have to spare, up to 2 cups) of ginger bug (see recipe here) - I read once people using water kefir grains too but haven't tried it myself
2. Bring to boil and simmer on low for about twenty minutes.
3. Add sweetener and let cool down to room temperature.
4. Add the ginger bug and pour the root beer to ferment in a 5 liter Picklit jar or some other big enough glass jar (or several smaller jars). Leave to ferment for one or two days in a warm place. Don't leave out for too long, it can get alcoholic.
5. Transfer to bottles and leave out for an extra day or two to get some carbonation in the root beer. Move to fridge. I find that it gets better after a while in the fridge but technically it is ready to drink now.