All tea made from the tea plant has caffeine, and that amount can vary dramatically:
from about 14 mg up to over 60 mg per cup.

Knowing what causes this variation can help you choose your tea more confidently.

Caffeine content is not defined by tea type. Black tea, green tea and more can all be made from the very same plants. Caffeine content cannot be increased through tea processing, so tea leaves picked to the same standard at the same time and place will have the same caffeine content, regardless of how they have been processed.

It is a common misconception that black tea has more caffeine than green tea. Instead, we have to look at how the tea was farmed, when it was picked, and how you choose to brew it.

Which teas have the most caffeine? Here are the determining factors:

Once we understand what affects tea's caffeine content, we can make informed decisions to find the most and least caffeinated tea and brew style for each tea type. Let’s cut past the common myths and look at where each tea really stacks up for tea caffeine levels.

• • Black tea’s caffeine range:
  as low as 14 mg per cup for larger leaf, cooler brews
  and as high as 61mg per cup for young pickings and hot brews

Black tea has a reputation for being the most caffeinated tea. The old thinking was, the darker the tea, the more the caffeine. It turns out that black tea’s reputation as a high caffeine tea is only observed when the tea is brewed at higher temperatures and with smaller leaf material (crushed tea bag dust). 

If you are looking for higher caffeine tea, you can still reach for black tea. There are many small, early harvest buddy black teas out there (like Jin Jun Mei and more). Look for early harvest, small leaf teas growing with biodiverse competition. Many black teas also stand up well to full-boil brew temperatures for the maximum caffeine.

• • Oolong tea’s caffeine range:
  between 14mg and 61mg per cup, depending on brew temperature and growing conditions

Oolong tea is one of the most diverse tea types, with countless growing regions and finishing techniques. The caffeine content in oolong can vary just as much. 

On the one hand, oolong tea is generally made with larger, later season tea leaves. In general, larger leaves and more mature leaf material contain less caffeine than an younger, small buds harvest from the same plant.

On the other hand, high-quality oolong teas grow in tremendously biodiverse microclimates like Daping village in Anxi or the Wuyishan Ecological Preserve. Biodiversity can stimulate more caffeine production, as can shady (misty mountain) growing conditions.

Finally, oolong loves to be brewed at a full boil, which guarantees a higher caffeine extraction than the same tea brewed cold.

• • Pu’er’s caffeine range: between 14mg and 61mg

Pu’er  tea (普洱) - sometimes spelled pu’erh or pu-er - is finished with as little heat as possible and allowed to naturally age for many years. Some pu’er teas are stored for decades or more. Does pu’er have any caffeine left when it has been aging for so long?

Caffeine is a fairly stable compound; it does not change or degrade over time like many other elements of tea. This means we can expect the caffeine in pu’er tea to stick around.

Like black tea, pu’er will have more caffeine if it is made from young small bud material grown in the shade (high mountain clouds). Unlike black tea, many people prefer to brew pu’er at a lower temperature, which could mean lower caffeine (at least compared to a hotter infusion).

• • Green tea’s caffeine range:
  between 14mg and 61mg per cup, depending on picking conditions and brew temperature

Contrary to the old myths, green tea can be just as caffeinated as black tea -  if not more! With high-end green tea, there is a strong drive to pick small, early-harvest buds and delicate shade-grown leaves, all of which leads to higher caffeine levels. 

However, green tea is also traditionally brewed at a much cooler temperature than black tea. Compared to a hot infusion, cooler brews extract comparatively less caffeine. Of course, sweet, shade-grown green teas like the He Family’s Laoshan Green can stand up to hot water, so you feel free to experiment with temperature and leaf-to-water ratio.

• • White tea’s caffeine range:
  between 14mg and 61mg per cup

White tea is famous for its silvery, downy buds. These early-harvest shade-grown buds give white tea its distinctively sweet flavor and rich texture. The early picking time also produces higher levels of caffeine. 

Wait a minute - doesn’t white tea have lower caffeine levels than other teas? Not at all!

White teas often have more trichomes - that silvery down - than other teas. Because trichomes are hydrophobic, they require a longer steep time or hotter brew to release the same amount of caffeine. This is why some earlier investigations seemed to show that white tea produced a low caffeine tea, even though other studies consistently contradict this.

Trichomes are not unique to white tea. Black tea, green tea, and even pu’er can all be made with downy bud material.

Of course, like green tea, white tea also tastes great with a cooler brew. This means you have the freedom to play with both temperature and water-to-leaf ratio.

What about tea without caffeine? Sometimes you want to enjoy a hot mug without worrying about the caffeine. 

If you do not want to drink caffeine, stay away from chemically-treated decaf tea. These products are not truly caffeine-free and can legally contain up to 2.5% of their original caffeine content. Instead, look for caffeine-free herbal tisanes.

Many herbal teas do not contain caffeine, but not all tisanes are caffeine-free. Look out for cacao, yerba mate, guayusa and yaupon, which all contain caffeine. Instead, look for dried flowers and fruits, garden herbs like mint, and spices like ginger for caffeine-free sipping.

Some herbal teas in China are actually finished using traditional tea craft to give them the same level of complexity as traditional tea, without the caffeine. These include sweet potato leaf, wild crassicolumna, goji leaf, and jujube leaf.