It's dead-simple: make tea and put the sugar in while it's hot, then cool and ice it. That's all. Maybe some mint, maybe a bit of lemon.
But some sort of magic happens, and you end up with a pitcher of this beverage about which poems are written, which brings to mind slow lazy sitting-on-the-porch days and gracefully sprawling oak trees, which prompted legislators in Georgia to try to pass a law decreeing that any restaurant that offered iced tea on the menu had to offer sweet tea.
God rested on the seventh day, but early in the morning,
before the sun strained into the Southern sky,
she made sweet tea from scratch. She boiled the water
in a black kettle, put in the orange pekoe bags
and let them stand as the water perked, and then
she did what gods know what to do: she heaped in the Dixie
Crystal sugar while the brew was still warm as the day.
- From "Sweet Tea", by John Lane
Step 1: Boil Water, Add Tea, Steep.
Some people have special iced-tea makers -- one of my going-away-to-college gifts from an aunt was an iced-tea maker just so that I could make sweet tea without even having to walk to the kitchen. For much of my first two years there, I carried a bottle of homemade high-octane sweet tea with me to class, instead of coffee. Double strong, double sweet, it was dangerous stuff.
You could use a coffeepot if you're desperate and don't mind your tea tasting like burnt coffee. You could use a teakettle and a good pitcher. Or you could use a big pot; that's what I do, these days, since I don't have the right kind of pitcher.
Boil the water, then turn off the heat and add the bags of tea.
For tea, my grandmothers use Lipton or Luzianne, the big iced-tea bags for making several quarts at a time. One of my grandmothers adds a small bag or two of Constant Comment. For the ~3 quarts of sweet tea I made yesterday, I used two big Lipton iced-tea bags, two small bags of roasted chicory (herbal) tea, and one bag of barley tea from the Korean market up the street. (Not "authentic", but very tasty in a toasted-grain kinda way.) Adding a bag of some kind of spicy chai also works well.
I brew mine a bit stronger than the instructions call for, 10 minutes or so.
Step 2: Sweeten Your Tea.
I don't recall ever measuring the sugar for sweet tea. You could try, I suppose. Maybe it would work. But I can't tell you how much sugar to put in your tea. Sweeten it until it tastes good, and remember that it'll taste sweeter when it's hot than it will after it's chilled and iced.
My grandmothers use scoops of white sugar; I use brown sugar and honey. This time around, I put in what looked like a couple handfuls of brown sugar and a big round spoonful of honey, for three quarts of tea.
As an aside: I get tubs of local honey at the Berkeley Bowl, and have discovered that if I keep the honey in the fridge, it doesn't crystallize, doesn't attract ants, and has a really neat caramel-taffy texture.
Now is also a good time to add mint, if you have some around. Crush the leaves a bit before putting them into the warm tea.
Step 3: Chill Your Sweet Tea, Then Drink It Iced. Rejoice!
I used to have a big plastic pitcher for keeping sweet tea, but plastic is not the way to go if you're going to keep the tea around for more than a couple of hours. (Works fine if you're making a big batch to serve with dinner or a picnic, though.)
Instead, glass mason jars are an excellent solution, and just awesome in and of themselves. Decant the tea off into the jars, but leave enough room to dilute it a little if you've brewed your tea strong; add water to get it just right. For mine, when I can hold the jar up to sunlight and the tea is just barely transparent, that's perfect. (Dear Instructables: If someone wants to build a portable device that will measure the strength of coffee or tea by its optical density, that would make me very geekily happy.)
I usually leave the mint leaves in the jar, so that the tea gets more mint flavor over time. Also, since the tea will be cooling, don't screw the lids on too tight. That makes it harder to get at the tea later.
You can pour the warm tea straight over ice and drink it right away, preferably stretched out somewhere comfortable and shady. Or you can set the jars in the fridge to chill and have a tasty glass ready when it's 80F at 10am the next day.
To wrap the story all the way around, in my four-and-some years in Boston, there was one restaurant where I ordered sweet tea, and the waiter listened very patiently to my explanation of what "sweet tea" was, and then earned a special place in my heart by bringing me out a complete sweet-tea-making set: a teapot with hot water, a bag of black tea, a bowl of sugar, and a tall glass filled with ice.