Most restaurants don't like to waste anything so the tea stays in the container until it's gone. After a few hours at room temp the tea will start to turn. So the restaurants end up having bad tasting tea so it doesn't sell. I return many glasses of ice tea that is 'old'. Most managers don't know about tea, just use the automatic machine and think it's okay to let it stay there until it's gone. You can tell with the fist sip. Sad that so many get the old tea and think that is how ice tea is suppose to taste. Sun tea has the old taste if left in the sun for a couple of hours. I make a pitcher of ice tea every day. We drink tea instead of soda. My favorite is black tea.