Knowing the secret formula for Coca-Cola doesn’t interest me. Knowing the secrets behind brewing a good glass of iced tea is another matter.

That’s why I called Jim Morpeth. Nobody in town brews more than he does and nobody makes it better.

His three Country’s Barbecue locations serve 50,000 glasses of iced tea every month. That’s a million ounces a month.

“It’s my passion,” Morpeth says. “I’m real picky about it.”

Most of us are. With temperatures pushing 100 degrees, it is a Southerner’s drink of choice, though hot weather is only an excuse. We just like our tea.

Henrietta Stanley Dull’s 1928 primer for Southern cooks offered a recipe that became the standard. Here’s what she advised in “Southern Cooking”:

“Freshly brewed tea, after three to five minutes’ infusion, is essential if a good quality is desired. The water, as for coffee, should be freshly boiled and poured over the tea for this short time . . . Tea leaves may be removed when the desired strength is obtained … Tea, when it is to be iced, should be made much stronger, to allow for the ice used in chilling. A medium strength tea is usually liked. A good blend and grade of black tea is most popular for iced tea … To sweeten tea for an iced drink -- less sugar is required if put in while tea is hot, but often too much is made and sweetened, so in the end there is more often a waste than saving … Iced tea should be served with or without lemon, with a sprig of mint, a strawberry, a cherry, a slice of orange, or pineapple. This may be fresh or canned fruit. Milk is not used in iced tea.”

Milk? What was she thinking? Who would put milk in a glass of tea?

We’re not talking about hot tea served in dainty cups with little round sandwiches. We’re talking about iced tea served in a hardy glass.

That’s why I called Morpeth. His iced tea comes in large Mason jars. No sprig of mint or pineapple for him.

He starts with Black Diamond, a tea made in the South. “Why would you use tea that is made in England?’ he asks.

Avoid Lipton. “I like a smooth tea,” he says. “It has too much tannin.”

Morpeth stresses the importance of filtered water, free of chlorine -- and he’s not talking about bottled water.

“They contain minerals that affect the taste. If you don’t use filtered water you ruin the taste.”

Use a good grade of sugar, he advises. “We make a simple syrup out of it first.”

Country’s uses commercial tea makers but he doesn’t follow the recipe. Instead of adding five gallons of water, he adds three.

“You want it strong because when you add ice you weaken it.”

How does he like his?

“I mix two-thirds tea and one-third lemonade,” he admits.

No milk, of course.