Compared to proper hot brewing temperature of $212^ ext{o} ext{F}$ ($100^ ext{o} ext{C}$), how does sun tea thermal exposure differ?
Sun tea operates in a vastly different thermal space, often reaching temperatures well over $100^ ext{o} ext{F}$ but rarely boiling.
Proper hot brewing requires water near $212^ ext{o} ext{F}$ ($100^ ext{o} ext{C}$) to ensure rapid and complete extraction, as well as pathogen elimination. Sun tea, however, operates in a much cooler thermal environment. While intense solar radiation in places like Phoenix might push the water temperature above $100^ ext{o} ext{F}$ ($38^ ext{o} ext{C}$), it generally remains significantly lower than boiling. This low-heat steep is precisely what differentiates it from a standard hot brew and is what prevents the quick release of compounds, leading to the characteristic mellow taste. If the water in a sun tea jar does not get hot enough, the extraction process may simply mimic a very slow room-temperature steep, regardless of the sun's presence.
