Why do tea pros slurp loudly when they taste?
It looks ridiculous but everyone serious does it. What's the point?
Slurping aerates the tea — sucking it in with air across the palate atomizes it into a fine mist that hits all your taste buds and goes up into the retronasal cavity behind your nose (where most of what we call 'taste' actually happens). Same trick wine sommeliers and coffee cuppers use. Drink quietly and you'll notice maybe half of what's in the cup; slurp and aromatic complexity opens up dramatically. Practice over the sink at first — it splatters.
— Yurii — 931 Tea, 931 Tea