A common misconception about green tea is that it always has a bitter taste.
While green tea contains bitter compounds, it shouldn’t taste very bitter once it’s served.
A green tea that has a high bitterness is often undesirable. It might mean that it was prepared incorrectly, or that the tea itself is of low quality.
Where does the bitterness in green tea come from?
The main bitter compounds in green tea are caffeine and catechins.
Catechins are bitter. For example, EGCG and EGC are both bitter and astringent.
Hence, in order to have a balanced taste we need to adjust the brewing parameters so that the amount of these compounds does not overpower the rest.
Leaf to water ratio
If we’re using too much tea leaves and little water, of course the taste will feel very concentrated.
So you’ll feel more bitterness as well.
Likewise, a tea left steeping for too long will have a stronger flavor. This leads to more bitterness.
But this also has to do with temperature, as we’ll see next.
At lower temperatures, the rate of infusion is lower so we need to increase the steeping time to compensate.
While all green teas can be infused at a low temperature, not all them should be prepared with boiling water because they will immediately become too bitter.
This leads us to the next point, the specific type of the green tea itself.
Type of green tea
In general, higher quality green teas are infused at a lower temperature, but for a longer time.
Meanwhile, a low quality green tea such as bancha are prepared in boiling water for a short time.
In terms of Japanese tea, the teas with a higher amount of amino acids are of better quality.
This is so because high amount of amino acids like L-theanine and glutamic acid are responsible for sweetness and umami taste.
Caffeine and catechins are very soluble in boiling water, but not so much in cool water. Amino acids, on the other hand, are almost as soluble in cool water as they are in hot water.
In other words, when we prepare a tea such as gyokuro or high quality sencha, we are trying to increase the amount of amino acids in our cup while suppressing caffeine and catechins (and hence bitterness and astringency) by using a lower temperature.
The goal behind the shading process for tea is the same. Reduce the amount of catechins and increase the amount of amino acids.
A very low quality green tea such as cheap teabag will have a bitter and flat taste regardless of how we prepare it, because the quality is so low.
Remember, a good green tea that is prepared correctly should be easy to drink.
That’s the whole point, to drink green tea because we enjoy its flavor.