Combine the grated ginger, sugar, and filtered water in a clean and sterilized jar. Stir to combine and dissolve the sugar. Secure a clean towel with a rubber band or mason jar band.

Stir once a day. The ginger bug is ready to be used in ginger beer when bubbles are present. This can take 1-3 days depending on the temperature of your house. If you aren't ready to make ginger beer yet, feed your ginger bug by adding 1" of grated ginger and 1 teaspoon of sugar, stir well.

Heat the gallon of water in a large pot. Bring it to a boil. Add the grated ginger. Reduce the heat so the mixture simmers for about 30 minutes. Remove from heat and strain the ginger out. The strained liquid is ginger tea.

Add the strained ginger tea to a 1 gallon glass jar that has been sterilized. Add the sugar and lemon juice. Stir to dissolve the sugar. Set aside or in the fridge to cool to room temperature.

Strain your ginger bug and add it to the cooled ginger tea mixture. Remember to reserve some of the bug if you want to keep a cycle of ginger beer going (just follow the steps for ginger bug above and add the reserved bug). Secure a clean towel with a rubber band and set aside at room temperature to ferment for about 24-48 hours.

After 24-48 hours it's time to bottle. Transfer the ginger beer into sterilized bottles. Leave about ½ to 1" of headspace at the top of the bottles. Wipe the rims of the bottles and secure the lids. Let the bottles sit at room temperature for 24-36 hours. Refrigerate and enjoy!