Prepare all the ingredients: peel and thinly slice the fresh ginger, slice the lemon, and weigh out the ground turmeric.
Place all the ingredients into a medium saucepan and add the water. Bring to a boil. Once boiling, remove from the heat and set aside to cool completely for the flavors to infuse for at least 3 hours.
Strain the cooled mixture through a fine-mesh sieve lined with cheesecloth muslin/food grade muslin. Discard the contents in the sieve.
Lovely when served chilled, but if you prefer it warm, simply reheat the mixture. Serve between 4 glasses and enjoy with a slice of lemon (optional).