Rooibos is forgiving, which is why so many people brew it badly. Unlike black tea it does not turn bitter when you leave it, so a three minute steep is doing you no favours.
Give it five minutes
Boil the water properly, pour it over the bag and walk away for five minutes. The colour should go deep amber, close to the colour of black coffee held up to a window.
Skip the milk on the first cup
Taste it plain before you add anything. If it still feels thin, your water was not hot enough.
Reheating is fine
Rooibos survives a second warm up. Iced rooibos left in the fridge overnight is one of the best things you can drink in a Johannesburg summer.