Fill a large stock pot with 10 cups water, and then spoon in the sarsaparilla, ginger, licorice, dandelion, birch, and star anise.
Bring to a boil over medium-high heat, then turn down the heat to medium-low. Simmer for 30 minutes, and then stir in the sassafras bark, and continue simmering a further 15 minutes.
Turn off the heat, stir in the sugar until it dissolves. Next, allow the decoction to cool to room temperature - about 2 hours.
Strain decoction, discarding the herbs. Stir in the ginger bug, and pour into flip-top bottles - allowing at least 1 to 2 inches of headspace in each bottle.
Ferment the root beer at room temperature about 2 days, allowing more time during cold weather. Transfer to the fridge for 3 days to allow the bubbles to set, and serve cold over ice.
Alternatives to Ginger Bug. Ginger Bug is a starter for fermented drinks made from ginger, water and sugar. And it contains bacteria and yeast that culture homemade root beer and give it bubbles. Alternatively, you can also use an equivalent amount of kombucha, jun tea or water kefir. You could also use fresh whey from yogurt or kefir.Alternatives to cane sugar. You can use an equivalent amount of maple syrup, maple sugar, honey, coconut sugar or any other caloric sweetener.