It is much more important that you prepare the tea the right way according to which herbs you use!
Some teas support boiling, and others like peppermint should be prepared while poring hot water over a tea-filter slowly, but never boil, this would destroy the oils and the taste.
Buy a good book about herbal teas if you are interested in knowing the perfect way to prepare it!
To cool down teas would be safe if it is boiled properly!
But don`t keep it more than 3 days refrigerated!
I know a terapist who freeze the kidney-tea in small ice-cube bags. Like this you always have the right size ready made for your cleanse! It works well!
Does anyone have a Herbal-tea-book-suggestion?
Lillian