Does English Breakfast Tea equal Assam Tea

The most likely culprits are:

1. Steeping too long: 1-3 minutes, depending on the type and grade of tea.
2. Using water that is too hot or too cold: Again, this depends on the type and grade of tea.

Here is an excellent resource for getting these factors right:

On Steeping Time:

Green tea does not require much time. Too long a steeping time will result in more bitterness and a less balanced flavor. We recommend experimenting with a range of 1 - 3 minutes. Japanese green teas generally taste best at 1 - 2 minutes while Chinese green teas seem to prefer 2 - 3 minutes (the smaller leaves of Japanese teas will extract faster than the generally larger leaves of Chinese teas). Steeping time should be balanced with water temperature: the lower the temperature, the longer the tea can be steeped.

On Temperature

As a general guideline, green teas taste best when brewed at temperatures between 140°F - 185°F (60°C-85°C). The grade of the tea and the time of its harvest will also influence the appropriate steeping temperature. Green teas picked earlier in the spring will benefit from lower temperature brewing due to their overall higher levels of amino acids.

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The most accurate way is to use a thermometer to measure the temperature of the water in the kettle. One approach is to heat the water in your kettle to the desired temperature and then pour it into your teapot. Another approach is to heat the water to boiling and then let it cool down a bit before pouring into your teapot.

Read the whole thing for further background.

This blog article (citing numerous sources) claims that re-boiling water doesn't have any significant effect on tea taste. Here are some key points from it:

• Heating water above 50˚C already removes most of the oxygen from it, so neither once-boiled nor twice-boiled water contain significant amounts of oxygen.

• Triangle tests such as this one prove that dissolved oxygen by itself doesn't affect water taste.

• While oxygen could theoretically reduce tannin's concentration in tea, this effect is dwarfed by other factors, notably steeping time, water temperature, and water/tea ratio.

All this is not to say that water is unimportant. Water is important. Alkalinity is important. Salt content is important. Minimal iron content is super important. Dissolved oxygen is not important. [...] For brewing tea, coffee, or any other hot beverage, dissolved gases are irrelevant.