In Taiwan when you buy tea, the merchant will usually set out little white bowls with ceramic spoons, a bit of leaf and some hot water. Like making tea soup. It's the instant ramen of tea. And they proceed to let it sit in the bowl for 15 minutes and often longer. It allows the leaves to completely steep out into the water.
They do this to test tea. When you do such a long brew it is not necessarily delicious to drink, but it makes the tea totally naked in the little white bowl. You can't hide anything in a 30 minute steep. This is when a bad tea will show its colors and a good tea will truly impress. Although the broth of any tea will be intensely bitter and astringent this way, a good tea can 'huigan' or turn around into a sweet feeling finish.
I bring it up because I was talking to a couple fellas in the shop who visited Taiwan last week. Chatting about their tea experiences, they said the bowl style brewing really made an impression. It kind of re-invigorated my interest in spreading this kind of tea drinking to my fellow drinkers. I think I will use this more frequently in the shop because it is such a valuable learning tool.
In the States, it seems we've adopted gaiwan brewing as a way to test tea. This makes sense, as people who've never tried good tea would likely be totally turned off by a cold bowl of half hour infused oolong. But the gaiwan does allow the brewer to manipulate a tea. It's impossible for us not to. That's what the tool is for, being able to control brewing parameters precisely. And when you've gotten good at it, you can help a sub-par tea to taste pretty alright. I don't think this will change any time soon, as our community is still very young and not ready for bowl style as the standard. But it is a tool that maybe some new drinkers would find useful.