Steeping your tea allows you to impart the nutrients found in the tea leaves to the water or liquid you are steeping the leaves in; however, over-steeping imparts more nutrients and flavors from the tea leaves, according to a study published in a 2007 issue of the "Journal of Chromatography." Over-steeping your tea may result in bitter tea, but this can be avoided by utilizing a proper temperature to brew the tea. This means 106 degrees Fahrenheit for green tea and 200 degrees Fahrenheit for black tea, according to Planet Tea.
Over-steeping imparts more of the antioxidant properties of the tea into the liquid you consume. These antioxidants, such as ECGC, have been researched in regards to cancer prevention. The National Center for Complementary and Alternative Medicine states that this research has shown that green tea drinkers have decreased risk of cancers such as breast, stomach and skin.
Most teas contain caffeine; however, the longer your steep the tea leaves, the more caffeine is imparted into the liquid. Caffeine is bitter and may be a reason why people don’t over-steep tea. Unfortunately, you will miss out on the benefits of caffeine if you choose a shorter steeping time. Research from The National Center for Complementary and Alternative Medicine states that caffeine has been shown to increase mental alertness. This can lead to improved concentration and focus.
A review of research by José Luis Barranco Quintana published in the “Journal of the American College of Nutrition” states that tea consumption has a protective effect against Parkinson’s disease. Parkinson’s is a neurological disorder marked by trembling limbs, slow movement and poor coordination. This research directly ties higher levels of caffeine in the steeped tea to an increased preventative effect. Again, this shows that over-steeping may be more beneficial than standard steeping.