Many Chinese teashops use porcelain gaiwans to brew their tea when a customer wants to sample their products. Porcelain are a neutral material and using porcelain to brew tea will not affect the tea in terms of taste and aroma. Using clay teapots may affect the tea as seasoned clay teapots can change or amplify the taste of the tea.
I had noticed when teashops use a gaiwan to brew tea, the tea 'brewer' would sometimes use fancy moves when he or she brews the tea. He would open the gaiwan and used the cover to stir the surface of the tea or even perform some visual moves like using the lid to go round the rim of the tea bowl. All these moves would not improve the sampling of the tea. In fact, the tea would cool down much faster and would not infuse well. I believed that pu erh or high roast oolongs should use boiling water (as hot as possible) to bring out the full flavours of the tea.
Many tea drinkers I know are using gaiwans to brew their tea. A gaiwan is inexpensive. Likewise, a porcelain teapot is also inexpensive. I prefer using a porcelain teapot when I am trying out tea samples at home. I would also use porcelain when brewing tea like white tea or liu an. There is a higher chance of an accidental slip when I use a gaiwan (yes, I had a few accidents) than using a teapot. I believed teapots keep the heat better than gaiwans (especially more so in winter).
One last tip; continue to put your kettle on a boil before you pour the water into your teapot or gaiwan at each infusion. It will make your tea session better.
