Bring 1½ litres of water to a simmer and add the tea. Turn off the heat and allow to steep for 5 minutes. Strain to remove the tea leaves and return the brewed tea to the pot. Add the sugar and ginger and simmer for a few minutes, stirring until the sugar has dissolved. 

Add the pears and goji berries (if using) and simmer for about 30 minutes, until the pears are tender when tested with a small sharp knife – it should be able to be inserted and withdrawn easily. Allow the pears to cool in the syrup, as this will help them absorb the flavour. Remove the ginger, then serve the pears and syrup either warm or chilled.