Common questions about tea and caffeine include:
- How much caffeine is in tea?
- Does all tea have caffeine?
- Is it possible to remove caffeine from tea?
- What tea has the most caffeine?
- What risks are there from the caffeine in tea?
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All “real” tea naturally contains caffeine. Real tea includes black, green, oolong, white, and puerh teas. They all come from the leaves of the Thea sinensis plant.
(Note: Herbal teas, such as chamomile and rooibos, are not “real” tea because they do not contain the leaves of the Thea sinensis plant. Herbal teas are classified as tisanes. They are naturally caffeine free with the exception of yerba maté. Read more about the types of tea and herbal tisanes here.)
The caffeine contained in the leaves of the Thea sinensis plant is water soluble. Whenever you brew tea using a teabag or loose tea, the caffeine in the tea leaves is drawn from the tea leaves into your mug or pot of tea.
Decaffeinated teas have most of their caffeine removed, most often using a chemical extraction process.
How to remove caffeine from tea at home without chemicals
Many people think that removing the caffeine from tea is as simple as infusing tea for 30 seconds, pouring it out and brewing the tea leaves or tea bag again.
But does that really extract the caffeine from tea?
Studies show that a 30 second infusion removes only a minor amount of caffeine, often less than 10%. Tea needs to be brewed for at least 3 minutes to remove half the caffeine, while 15 minutes is needed to remove all of the caffeine.1
So if you’re looking to reduce your caffeine consumption, you might consider pouring out your first brewing and adding more hot water for a cup of tea with less caffeine. However, doing so will decrease the flavor of your tea, with the amount of flavor decreasing the longer your first brewing is.
If flavor is important to you, you may want to enjoy drinking your first brewing in the morning, and simply have herbal tisanes for the rest of the day.
How much caffeine is there in tea?
Many tea drinkers think that keeping your caffeine intake down is as simple as choosing green tea over black tea. But it isn’t as easy as this.
The amount of caffeine in tea depends on the type of tea plant, growing season, processing method, brewing time, and more. That means how much caffeine is in tea varies between the different types of tea – green, black, white, oolong, and puerh.
The average 8 oz. (240 ml) cup of tea contains 15-70 mg of caffeine. An 8 oz cup of decaffeinated tea still contains a small amount of caffeine, usually less than 12 mg.
Coffee vs Tea: Caffeine Differences
Tea and coffee contain the same type of caffeine. However, they affect your body differently.
When tea leaves are infused, the caffeine combines with the tannins in tea. This causes the caffeine in tea to be released more slowly than the caffeine in coffee. It also causes the caffeine in tea to have a longer effect.
In coffee, the caffeine effects the blood through the coronary system, causing an increased heart rate.
In tea, caffeine stimulates the cardiovascular system and the central nervous system. It increases alertness and concentration while eliminating fatigue.2
Green Tea vs Black Tea: Which has more caffeine?
It’s commonly thought that black tea has more caffeine than green tea. However, the amount of caffeine in each type of tea varies based upon how the tea was processed, harvested, brewed, and more.
So some black teas have more caffeine than some green teas, while some green teas have more caffeine than black teas.
However, black tea is a better stimulant than green tea. When black tea is processed it oxidizes. Oxidation partially separates the caffeine from the tannins. This allows the caffeine in black tea to enter your bloodstream faster than the caffeine in green tea.2
Tea and Caffeine: Are there any risks?
Caffeine affects everyone differently. If you’re like me, a cup of tea keeps you alert for hours. For others, it barely has an effect. It’s important to know how caffeine affects you, and how much is too much for you.
Caffeine may cause an allergic reaction in some people.
Too much caffeine consumption can cause headaches, depression, adrenal fatigue and insomnia.
Caffeine may also have an addictive quality and you may feel like you have to have your daily cup of tea or you can’t function. If you suddenly remove caffeine from your diet, you may experience symptoms such as headaches and fatigue until your body adjusts.
Consult your healthcare provider for more information, especially if you are pregnant or suspect you have a caffeine allergy.
1‘Tea preparation and its influence on methylxanthine concentration,’ appeared in Food Research International Vol 29, Nos 3-4, pp. 325-330. (FRI is copyright of the Canadian Institute of Food Science and Technology)
2Gascoyne, Kevin. Tea: History, Terroirs, Varieties. Richmond Hill, Ont.: Firefly, 2011. Print.