( And why you might want to pay attention to your kettle )
Oxidization is the process that the tea leaf goes though to be classed as either a black, green or white tea. Both green and white teas are less oxidized than black teas. The more oxidized a tea is, the hotter water has to be to bring out the desired taste from the tea leaves.
With black teas the boiling water brings out the rich, complex flavour that is so recognizable. If the water is not hot enough, the tea might taste weak and lacking in depth simply because not enough tannin is released. If too much tannin is released then the result is bitter and astringent. So finding that sweet spot is the trick.
With green and white teas you need that lower temperature to bring out the freshness and sweetness of the leaves, without extracting to many tannins resulting in bitterness. If you are finding green tea bitter it can often be one of three things. Try using a little less tea, make sure your water is not too hot or try a shorter steeping time.
Less is more with white tea brewing. Using a teaspoon of leaves per cup, boil your water and leave to cool down for three minutes then steep your tea for a minute or two. White tea is good for several infusions, so brew, enjoy, top up and enjoy again.
Three really is the magic number here. Using a teaspoon of leaves per cup, boil your water and leave to cool down for three minutes then steep your tea for no longer than three minutes.
Using a teaspoon of leaves per cup, freshly boiling water and steep for four or five minutes.
Use two teaspoons per cup, freshly boiling water and steep for at least five minutes although ten minutes is probably better. A little sugar can really intensify those fruity flavours.