Others have noted like myself the sponge effect of tea ie larger grade leaves in a pot dropping the water level as they expand. They expand so much it is like a magician pulling tea leaves out of a hat. A sponge is mostly air. This effect seems to disappear in finer grade oxidized sizes. I conclude oxidation removes air space. Ive never seen an estimated of how much tea leaf membrane is air. I assume this has something to do with converting CO2 to oxygen. The cell structure instead of flat and dense must be porous like boxes. However if so why doesnt tea give up its taste in the first pot for less oxidized greens like the blacks. If I conjecture that tea is mostly air why doesnt it disintegrate instead of remaining intact. Im just rambling about some tea imponderables I notice everyday.
Jim
PS What tea leaves were the Gypsies using for fortune telling? Did this predate the introduction of tea in Europe. If so why wasnt Italy or the Arabic area the source of tea trade?