Though they are similar, there are some silly differences between sweet tea and sweetened iced tea, depending on the brewing method. For perfect sweet tea, you should brew the tea using fresh water that is right off the boil, adding sugar to the water in hot.  On the contrary, for sweetened iced tea, you must add any brewing way and sweetener you want. Many people use the cold brewing process to reduce the acidity and agave syrup as sweeteners.