We get asked this question a lot: Does green tea have caffeine? If so, how much? Simple question. Not such a simple answer. What makes this seemingly straightforward query a bit hard to nail down, is that asking about the amount of caffeine in green tea is like asking how much alcohol is in red wine - the answer can vary dramatically depending on the specific product in question. Please note that our guidelines below should be thought of as generally close rather than 100% accurate. We like to avoid speaking in certainties when it comes to something as complex as tea.
But complicated questions don't scare us: let's dive in.
Does green tea have caffeine? Yes, but…
All tea made from Camellia Sinensis (Remember our post of black and green tea?), the plant responsible for tea, contains some level of caffeine. Sencha for example tends to contain 3-4% caffeine by dry weight. The Camellia Sinensis plant produces a complex array of chemicals, caffeine among them. The presence of caffeine in the leaf is a deterrent to many of the insects looking to snack on the leaves - essentially acting as a natural pesticide. The final amount of caffeine ending up in your cup depends on many factors including the way in which the tea was grown, processed, and prepared.
Terroir and farming techniques impact on caffeine
Depending on where and how a tea is grown, the chemical composition of the leaf can vary greatly. As a result, teas that are grown naturally without the aid of robust pesticides tend to produce more caffeine due to the fact that they need to fend for themselves entirely. This is one of the reasons organic teas often have a more bitter profile (caffeine presents itself on the palate as bitter). Many higher elevation Sencha from Shizuoka (Honyama, Kawane, Shimizu) are grown in a very hands off manner and tend to have a brisk minerality and a soft astringency that is a result, in part, from elevated levels of caffeine as well.
Interestingly, certain tea cultivars will have more or less caffeine naturally much like how apples have such a wide variety of color and flavor. Another farming technique that can have an impact not the level of caffeine, but how your body processes the caffeine, is shading. Shaded teas like Gyokuro, Kabuse and Matcha all are covered from sunlight prior to harvesting. When the leaves are covered more of the naturally occurring chemical L-Theanine is remains in the leaf. L-Theanine slows the absorption of caffeine into the bloodstream and while the tea itself does not have less caffeine, it can be less irritating to those with a caffeine sensitivity.
Image Copyright Kitagawa Kiyohisa
Tea processing and impact on caffeine
After the tea leaves are picked they are quickly steamed to halt any oxidation of the fresh leaf. The length of steaming can range from 10 seconds or so (Asamushi) to 45s or more (fukamushi). The length of steaming does have an impact on the amount of caffeine in the leaf. Caffeine is water soluble and can break down with longer exposure to steam. So it makes sense that longer steamed teas would have slightly lower levels of caffeine. The same logic holds for teas that are roasted after processing like Houjicha. Houjicha goes through a secondary roasting process much like coffee - and the heat applied to the leaf causes some of the caffeine to leech out in the process. So if you are looking for a lower caffeine option, Houjicha is a great choice. You can lightly roast your tea leaves at home too - just heat a dry skillet and toast over medium heat for about 1 minute.
Houjicha is lower in caffeine due to being roasted
Caffeine levels and brewing temperature
While you can’t control farming or processing techniques, brewing is the one thing customers can control in the final outcome of caffeine in their cup. Caffeine is, as mentioned earlier, water soluble and is released more quickly in higher temperature water. If you are looking to limit caffeine, brewing in water below 180F (82C) will indeed release less caffeine. We can assume that brewing roughly 5-6g of Sencha leaf at 180F (82C) is going to release about 60-80mg of caffeine.
Image Copyright Kitagawa Kiyohisa
We can’t stress enough that it is quite hard to determine precisely how much caffeine is in green tea, so take this as a general guideline and not a precise amount.
A quick guide for understanding caffeine in green tea
- All green tea contains caffeine: cultivar, growing conditions and garden management play a large role in how the leaf creates and store caffeine
- Teas that are steamed longer and roasted contain less caffeine
- Brewing your tea in water below 180F (82C) will release less caffeine
We have an extensive collection of Japanese Teas, some of them rarely found outside of Japan.
And If you need some help choosing the right tea for you, please contact us!