The Best Way To Make Sun Tea, According To Science

As it turns out, the best way to make "sun tea" — tea that's brewed in the heat of the sun and then cooled to be enjoyed over ice — doesn't actually involve the sun at all. Though there's certainly an Insta-worthy elegance to leaving your tea out on the porch to brew, the truth is that it's actually safer to let the work be done inside. Why? It's easier for bacteria to grow in the tea when it's outdoors, and nobody wants bacteria ruining their afternoon. 

Per The Kitchn, tea that's sitting out in the sun for many hours will spend a lot of time in the bacteria danger zone of 40 degrees to 140 degrees Fahrenheit. Brewing your tea in the sun, then, is a bit like frying your egg on the hot sidewalk — it definitely illustrates high temperatures, but you wouldn't want to eat that egg off the pavement! So, if you shouldn't make sun tea in the sun, what's the solution? 

Armed with a thermometer and several test pitchers of tea, J. Kenji López-Alt tackled this question for Serious Eats. Brewing different quantities of tea bags in a variety of container types, from glass jars to deli-style containers, he found that four bags per quart was the best ratio, while glass produced the cleanest taste. As for the ideal sun tea brewing method, that bit may surprise you.

Enjoy iced tea the safe way, says López-Alt

Here's how to make sun tea the safe way, according to López-Alt for Serious Eats. Sadly, it involves the boring old fridge instead of the sun or the porch, but you'll forget the process when you're back outside, having a cool drink on a hot summer's day. The food writer made tons of different batches of tea in varying conditions, including the classic sun tea, brewed directly in sunlight; another brewed in the sun, but in an opaque container; and another brewed outside, but in the shade. Others were brewed inside: on the countertop, in the fridge, in a hot water bath, or like regular hot tea, then left to cool.

As it turned out, most of the batches tasted pretty much the same, per López-Alt. But there was an outlier: the tea that was brewed in the fridge, which is ironic considering sun tea is meant to be consumed cold, anyway. To try this yourself, let your tea brew in your container of choice in the refrigerator for a few hours, then sweeten it. At the end of the day, this is the safest way to make sun tea. The Pioneer Woman, however, reminds us that no matter the temperature of the water, the tea will eventually infuse into the water. The minutiae of time and methodology is mostly up to you!