Homemade Ginger Ale

Into an empty 2-liter soda bottle, put the ginger root, sugar, yeast, and lemon juice. Fill the rest of the way with water. Screw the cap onto the bottle as tight as possible. Shake the bottle well, then leave at room temperature until the bottle is too hard to squeeze, about 2 days. Refrigerate. To serve, pour through a tea strainer.