Put the water with 3 - 6 tablespoons of sugar in a saucepan on the stove and slowly bring to the boil.
Poke the blueberries once with a sharp knife and add them to the water.
As soon as the water is hot, hang the tea bags in and let them steep. Be careful, the tea bags shouldn`t be cooked, so take them out beforehand.
Let the tea simmer for half an hour.
Let the tea rest until it has completely cooled down and then pass it through a fine sieve (but preferably through a linen cloth so as not to keep any bits in the tea).