Re: As you might expect...
"The problem with the Dutch is that they always make tea of boiled water"
Your Dutch colleague is quite right; you shouldn't use boiling water on some tea because it will scald the leaves and ruin the flavour.
"The best temperature for brewing tea depends on its type. Teas that have little or no oxidation period, such as a green or white tea, are best brewed at lower temperatures between 60 °C and 85 °C (140-185 °F), while teas with longer oxidation periods should be brewed at higher temperatures around 100 °C (212 °F). The higher temperatures are required to extract the large, complex, flavorful phenolic molecules found in fermented tea, although boiling the water reduces the amount of dissolved oxygen in the water."