One of the most popular teas in summer is “sun tea” – tea that is brewed by leaving a clear container with tea in it out in the sun for a few hours. While this has a certain appeal because it is such an easy process, not to mention the fact that tea looks awfully pretty in the sunlight, it bears some risks. The essential problem with brewing tea using this method is that sun tea will not get hotter than 130 degrees fahrenheit (54.44 C), which is not hot enough to kill bacteria in the water or in the tea leaves. Standard brewing processes for hot tea are always hot enough to ensure that any undesirable microbes are killed, eliminating this risk. In addition to the insufficient heat, sun tea generally sits around for a lot longer than hot tea, giving the bacteria a chance to multiply and become problematic. In essence, the sun tea method is a lot more like making tea in a contaminated Petri dish than a teapot.
“Using the natural rays of the sun to make tea is fun and popular in the summer. However, using such a method to make tea is highly discouraged. Sun tea is the perfect medium for bacteria to grow. If the sun tea has a thick or syrupy appearance, it may be due to the presence of a ropy bacteria called Alcaligenes viscolactis. Ropy bacteria are commonly found in soil and water.”
The quote above is from Is Sun Tea Safe?, on the Colorado State University Extension SafeFood Rapid Response Network.
Of course, every summer people brew and drink gallons and gallons of sun tea and do not get sick. This does not mean that there is no risk. If you’re okay with the possibility of stringy rope-like bacteria breeding in the tea you drink then there’s no reason to change your ways. But I don’t see much reason to continue using this method after finding out about its inherent dangers, even if the statistical risk of illness is not great. Plus there are excellent alternatives for making iced tea.
Boiling the water before you make sun tea can prevent the bacterial risk, but once you’ve gone to that effort you might as well just hot brew the tea in the normal fashion and then cool it in the refrigerator. But if your goal is to avoid using the stove on hot days, an ideal solution is to cold-brew your tea. I believe that there is a common misperception that tea leaves require boiling, or at least very hot, water to release their flavors into the water and transform it into tea. The reality is that steeping tea leaves in cold water for a few hours in the refrigerator produces excellent tasting cold tea. This method also works quite well for many tisanes (non-tea infusions). I usually use a Mason jar with loose leaf tea and then strain the tea into a second Mason jar when it is sufficiently steeped, usually about six hours. This time can be longer or shorter depending on how strong you prefer your tea and you can tell by the color when it’s ready.
What it all boils down to (or doesn’t boil at all in this case) is that there’s really no compelling reason to make sun tea when you want to drink iced tea. You can take those same containers you’d put out on your porch and put them directly into your refrigerator instead. The tea tastes every bit as good or better and it’s much safer. While drinking tea contaminated with Alcaligenes viscolactis will just make you sick, not kill you, it seems preferable to avoid any possibility of its stringy, ropy presence in your glass of tea.
If you need more evidence, Snopes.com, the reliable source for verifying or dispelling rumors and urban legends, supports the view that sun tea is unsafe.
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