I was surprised to not see a menu but staff can explain the teas and seeing them dry and loose, and being able to smell them, was an unusual way to choose.
Tea is served by the pot (two cups) and there are cakes available too.
Yumchaa Soho has two floors, ground and basement, and there's normally more space downstairs.Free wifi is available, although it wasn't working when I visited.
There are other branches.
Saturday and Sunday: 10am - 7pm