There are 2 subjects that can spoil a tasty family meal: illnesses and politics (unless everybody votes for the same party). Several members of my family are in the medical field, so I often get to listen to graphic description of patients' conditions while eating. And some diseases don't even need a description to cut my appetite.
To enjoy food or tea, the state of mind is very important. That's probably why I prefer to look beyond the health benefits of tea. It's just not relaxing to think of all those diseases tea is supposed to protect us against. Tea won't make us immortal, but a perfect cup of tea can taste divine.
But there is an even more disturbing thought: tea could be unhealthy. In this regard, the most recurring fear is that of lead in tea accessories. And this is not something that can simply be thought away. To find my peace of mind, I tested various ceramics 2 years ago. On the Teachat forum, others have also obtained negative results.
I think we can put this concern about lead to a complete rest for most tea ware. Most earth ware (like Yixing pots) and porcelain are fired at temperatures above 1200 degrees Celsius to succeed. Even potteries made at low temperatures still exceed 800 degrees Celcius. Lead, however, melts at 327.5 degrees Celsius. Fired at a temperature above 327.5 degrees, lead would melt and flow to the bottom of the piece (easy to spot by eye). So, the only way there could be substantive amount of lead is if it were added after the firing, as part of a decoration. A plain earth ware teapot would loose its shape if it contained melted lead. The main risk I see, therefore, are accessories with fragile (color) ornaments that look like having been added after firing. These decorations may (or may not) contain lead.
6 hours ago