Tea Sunrise
I am glad you find Sevencups useful. I have never ordered from them, but just looking at the info and prices, they look the most authentic to me, above the other mentioned ones.
I am treading sandy ground here as I have never systematically tested them, so don't take it as a recommendation from me.
The following applies only to Chinese green tea, and not to Sencha of which I know nothing of.
Yes, when it comes to green tea, size is important. The general assumption is younger the tea shoots, the higher the grade.
You can see some pictures of tea shoots over here.
formatting link
Tea shoots generally are smaller than tea leaves. The Chinese tend to grade it as a % of a fully matured leaves.
So a high grade leaves will usually be one bud with 0 to 2 slightly unfurled leaves. (i.e. the leaves are hardly opened)
Whereas oolong tea may be 1/3 to 1/2 the size of fully matured leaves.
Back to green tea in the realm of tea shoots...
High quality tea shoots tend to be fairly (but not overly) complete (not fragmented) and uniform (but not overly so, as it would then be a fake).
The youngest tea shoots (picked earliest spring) tends to be the fattest. So here you have a case where they are the youngest but slightly larger (fatter) than later pickings.
But leave the tea buds a few days longer and they will get quite large, and corresponding lower quality.
This is a generalisation of the small-variety Chinese plants.
Into the realms of different varieties of Chinese green tea ...
Biluochun is usually the case of smaller the better ... When grading they into account of age and size.
Longjing is usually age, well, that is my tea garden practice anyway.
TPHK is made from Shi Da Cha (the big variety) which is exactly the opposite (stouter, larger, the better). But they are still harvested really early (first 20 days in spring only).
But TPHK is not typical of Chinese green tea. This type of Chinese tea is found only in Anhui province.
In summary, age is usually the determining factor.
When looking at external appearance, we look at size, fattiness, aroma, uniformity, PROPORTION of buds and leaves, how open the leaves, and to much smaller extent tea liquor colour/brightness are etc.
All these factors can give indication of age.
There is another page of materials here
formatting link
But there most important thing is TASTE - it is the only thing that doesn't lie.
If you don't mind, can I post your question and this discussion to my site? I will love to share the discussions with my visitors.
Hope it helps.
Julian
formatting link