For this recipe, make sure you have one of those pop-top bottles to keep your ginger beer. You'll need your ginger bug and some ginger, sugar, and a lemon. This is mostly non-alcoholic.
Make some ginger tea. Put the water in a pot and bring to a boil. While it’s heating up, add 40g ginger and 100g sugar along with some zest from the lemon. Once it’s boiling, remove from heat.
Wait for the tea to cool down to room temperature (<90 F). It’s important that we don’t kill the yeast and bacteria in the ginger bug, or ruin the flavor of the lemon juice.
Mix in the 100g ginger bug and juice from the lemon, then strain it out. Pour the mixture into the bottle, the cap it up. Put a label on it with the date, then wait 1 week. It can build up quite a lot of pressure, so make sure you open up the bottle regularly to prevent an explosion, but not so often that it doesn't become carbonated.
Once it’s finished, chill it in the fridge. This is important to keep it there to slow further fermentation.