Steep the rooibos tea bag in the boiling water for 5 minutes. Discard the tea bag and pour the black tea into a small saucepan. Add the honey and simmer over low heat until the mixture forms a light syrup. Allow to cool. Fill a cocktail shaker with ice and add in the rooibos syrup, lemon juice and Esperanza. Shake to combine and pour into a highball glass. Add ice and top up with soda water. Garnish with the dehydrated lemon.