Black tea water: Does boiling water first make a difference? When I make black tea, I usually put the leaves (or tea bags) into cold or room-temperature water before I start boiling it. I've noticed that certain cultures always insist on first boiling the water, and only putting in tea leaves once it reaches a full, rolling boil.

Does boiling the water before putting in the leaves make a difference? I tried both ways and couldn't find a difference in taste. It seems like boiling for more than a few minutes means both would have similar levels of oxygen (not sure why that would make a difference).

To clarify: I personally *boil my tea leaves (or bag) for several minutes, as in 10-20 minutes or more. It seems like the other popular way to make tea is to steep in boiling water for several minutes.

I would like clarity on whether putting the leaves/bags in cold water makes a difference, especially given the time-scale of boiling (should it be shortened).
As you're heating the temperature of the water will rise at different rates, depending on the amount of heat, on the quantity of water, and on whether the pan is covered or not. With the tea in the pan, this would create an infusion gradient, as the temperature rose over a varying number of minutes. 

If you boil the water first, then infuse, you've fewer variables: the quantity of tea and the quantity of water. So you'll have less to adjust to get the brew perfect.

I don't see how you could brew even the finest black tea for 10-20 minutes without over-extracting it, producing a stewed, bitter flavour that dries the tongue.