Bring one gallon of filtered water to a boil with the sassafras root bark.

Once boiling, mix in sucanat and allspice. Once completely dissolved, remove pot from heat and strain with a mesh strainer (stainless steel not plastic) lined with a white cotton dishtowel into a 2 gallon glass jar (sources).

Add one more gallon of filtered water and stir. Wait for the mixture to cool slightly (about 30 minutes) and then stir in the juice of 2 lemons. Wait for the mixture to cool to 118 °F/48 °C or lower and then add 1 1/2 cups of starter. Note: if the mixture is too hot, the heat will kill the starter culture so be sure to wait until it is only warm to the touch. If you let the mixture cool and sit too long on the counter, however, you introduce the chance for mold. So be sure to add the starter at the appropriate time.

Cover your container with a white, unbleached cloth secured with a large rubber band. Leave on the counter for 5-7 days depending on the weather (the warmer the weather, the shorter the brew time).

When the initial fermentation is complete, the root beer is ready to drink as is. If you desire enhanced carbonation, proceed to the bottling step. Fill your soda bottles (sources) and cap them. Leave some room (I leave 2 inches) at the top of each bottle to allow for carbonation. See this link on homemade soda bottling for visual and written instructions.

Leave at room temperature for a day or two longer to carbonate. Then refrigerate and enjoy!

Only open the root beer bottles in the kitchen sink and when the bottle is very cold to prevent messy explosions!