Why does homemade iced tea sometimes turn cloudy when refrigerated? Is this preventable?
Cloudiness in tea is caused by caffeine and tannins bonding with each other when tea is refrigerated or iced. The hotter the original brewing water the more caffeine and tannins are extracted from the tea leaves, and the murkier the beverage will be. To determine the brewing temperature at which clouding first appears, we made several batches (each with five black tea bags and 1 quart of filtered water) at temperatures ranging from room temperature (68 degrees) to boiling (212 degrees) and refrigerated them overnight.
The next day, we saw signs of cloudiness in all of the samples that had been brewed above 100 degrees. The refrigerated room-temp brew, meanwhile, was still crystal clear but tasted weak compared with teas brewed with hot water. Increasing the number of tea bags and steeping at room temperature gave us a clear, smooth-tasting tea that wouldn’t go murky when cold. To make it: Steep 10 tea bags in 1 quart of room-temperature water for eight hours and then refrigerate or serve over ice.