My old landlady knows ice tea. I've seen her tear through tea (and servers who don't bring enough lemon or who pour refills into glasses of melted ice) at some of the best restaurants in Tacoma.
So when she made herself sick with a batch of home-brewed tea, I thought it was worth a reminder: tea is a great breeding ground for bacteria; brewed in the sun (and left there too long) such tea can give you a terrible tummy ache.
It happened to my old landlady last week, when she sun-brewed a jug of tea that she left in the rays for two days. Those ropy things that grew in the jug weren't some kind of new sweetener. Those were Alcaligenes viscolactis, a bacteria.
Dry tea leaves contain low levels of bacteria, yeast and mold. They can grow to high levels if stored at room temperature or above for long periods.
Alcaligenes viscolactis can turn up in any kind of tea, but sun-tea drinkers are particularly susceptible, as the thing bacteria loves most is warm, wet environment.
You won't find sun tea at restaurants. They're supposed to follow food-safety procedures when brewing tea. This includes brewing with water that's at a minimum 175 degrees, not holding tea at room-temperature for more than eight hours and discarding unused tea after that time.
What can you do at home? Don't keep your tea in the sun too long and only brew enough to get you through the next 24 hours.