350g white sugar
3 Tbsp (about 100g) freshly grated ginger
Extra 4cm piece ginger, thinly sliced
1/4 tsp active dry yeast
Juice of 2 lemons
1.8L filtered water (do not use tap water)
Extra lemon, thinly sliced, to serve
Combine sugar, water and grated ginger in a small saucepan over a medium heat. Simmer for 4-5 minutes or until sugar dissolves. Cover and set aside for 1 hour to cool. Strain through a fine sieve, pressing mixture to get the most flavour from the ginger.
Divide sliced ginger between 2 clean 1.25L plastic PET bottles with tight-sealing lids. Divide yeast and lemon juice between bottles. Pour equal amounts of ginger syrup and filtered water into each, then secure lids tightly. Shake vigorously for 2 minutes to dissolve yeast, then store in a cool place away from direct light for 3-4 days. Release lid carefully (it will be fizzy) and serve with lemon slices. Refrigerate once opened and consume within 1 week.