Which Tea has the Highest and Lowest Caffeine Content?
By kborowsky September 11th, 2018
Black tea typically has the most caffeine of all the tea types. One of the reasons for this is a longer infusion time versus green along with higher steeping temperatures, typically boiling. Because black tea is oxidized, it allows more caffeine to be extracted from the leaf versus other types of tea.
There are other influences that can alter the caffeine content, including which part of the plant the leaf comes from, altitude and local conditions, leaf grade, type of tea, fertilizer used, and much more.
As a general rule, the Assamica tea variety is higher in caffeine than other varieties. These are teas grown in India, Africa and Sri Lanka. Assam is a classic example of this tea variety. Furthermore, the teas can be processed in the orthodox fashion (rolled) or CTC (Cut-torn-Curl). Orthodox teas are rolled and graded depending on the leaf makeup and size. If you see the term "broken" grade, it means that there are smaller bits and pieces of tea which mean there is more surface area, and thus more caffeine extraction ability.
CTC tea is where the tea is cut into smaller pieces via a machine and then rolled into little balls. Many African teas follow this method. The smaller balls allow for rapid, strong infusions.
The Chinese variety of tea leaves tend to be lower in caffeine. Lapsang Souchong is made from lower, older tea leaves, it is amongst the lowest in terms of caffeine content. Older bushes, typically found in certain areas of China also result in lower caffeine levels. Some shade grown green teas like Gyokuro tend to have higher caffeine levels than their non-shaded cousins.
Because there are a myriad of ways caffeine is measured and when it's measured - it's hard to say which tea variety has the absolute highest and lowest amount of caffeine. There are literally dozens of factors that make up the caffeine content in tea, and any tea company can seize one aspect and declare that this is the highest caffeine tea you can buy, when it might be taking data from a particular moment in time that is 'ideal' but changes later when it is being processed.
At the end of the day - drinking black tea will yield the highest caffeine as a rule of thumb, with green and white teas having lower amounts. Will there be enough variation between one type of black tea versus another to make a noticeable difference? Probably not. And don't forget, there are other components in tea that can increase your overall performance. EGCG, L-theanine are found in tea in varying amounts - and these too can increase concentration and awareness without giving you a caffeine jolt and crash.
The one benefit to drinking tea is that there are lower overall amounts of caffeine, allowing you to drink more. Daily recommended caffeine should be about 400 milligrams, which is 4 "cups" of coffee, but cups being 8 ounces, it really means 2 large cups to a lot of people. With tea coming in around half the caffeine as coffee (45 per cup versus 90 for coffee) you can enjoy a lot more tea throughout the day.