Tea taste changes if watered down after steeping Why does the taste of tea change after watering it down after it's ready for drinking?

If you use 100% of water to make a cup of tea and then add 50% more water, the taste is not the same as when you make a cup of tea with 150% of water from the start. Why does this happen?

It doesn't happen to granulated coffee, but it does happen with bagged or free-leaf teas. I'm not a big fan of ground coffee, so I can't say anything about it.

I also know that nobody recommends watering ready tea down, but I haven't heard why yet. What causes the change of taste?
Water extracts flavor and color compounds from the tea leaves. Water can only hold so much of these compounds before it reaches the saturation point, where it cannot hold any more. Any flavors left in the tea leaves are unable to be extracted by the water. 

If you only add 50% of the water required to extract all the flavor and color from the tea you leave much of the flavor behind in the leaves, and the tea will taste strongest of the compounds that are extracted fastest. When you then add the other 50% of the water the tea will be weaker and taste different than tea that has been steeped in 100% of the water needed to extract all the flavor and color.