This is how I prepare the tea for myself...
I make a gallon at a time...The most effective ratio is 3 tablespoons tea with one quart of distilled water (3/4 cup per gallon). Add the tea to pot (glass or stainless steel) of cold water. After water starts to boil, reduce heat and "low Boil" for at least 20 minutes. Then add a little more water to bring liquid level back to start level. You can make it a bit stronger if you are comfortable with the taste...
Do not use aluminium or tin pots or containers.
Strain the tea through a piece of linen cloth, tea strainer or coffee press device.
Serve luke warm or cooler. Store the tea in a glass container.
You can add some "Stevia" or sweetener of choice.
The tea does not deteriorate in time because the herb is totally immune to mold and fungus.