When it comes to comparing tea with coffee or comparing different tea categories, the most discussed topic is caffeine content. While it’s safe to assume that any tea should have significantly less caffeine than coffee, this is more difficult for caffeine levels between tea types.
Based on general consensus we can assume the amount of caffeine to in tea to be the highest for pu erh tea and black tea and lower for green tea and white tea. However, according to one of our visitors, there has been some recent research that provides proof that green tea contains actually more caffeine than black tea. Here’s his question:
Apparently there is some minor controversy about the difference between the caffeine levels in green and red teas (referred to as ‘black’ here in the U.S.), and that some think that green tea has more caffeine than red tea, which is contrary to common assumptions. Recent technological developments helped discover this, some claim. Do you have any thoughts on this? Are you aware?
First of all, I would like to point out that it’s really hard to determine which tea has more caffeine than others. First of all, are we talking about the real content of caffeine per gram of leaf? Or per cup of x mg of tea? Determining the caffeine content per gram of leaf should be really easy as this is a chemical analysis. However, the result might not be relevant as what matters is how much we finally consume by drinking tea.
The are simply to many factors that can affect the amount of caffeine in a cup of tea, which makes it really hard to draw any general conclusions:
- Steeping temperature: the higher the steeping temperature the more caffeine the leaves will release. What also matters for researchers is that whether they should steep green tea and black tea both at the same temperature or at the usual recommended temperatures (e.g. black tea at 100 degrees Celsius and green tea at 80 degrees Celsius). Scientifically steeping both teas at the same temperature would make sense, but this would not represent how real tea lovers steep their tea and therefore it would also not reflect true caffeine content.
- Steeping time: the longer you steep, the more caffeine will be released in a cup. The same comment regarding steeping temperature is valid here: would you steep both green tea and black tea for the same amount of time, or follow how tea drinkers behave in practice?
- Crushed versus loose leaves: Crushed leaves will release more caffeine than full loose leaves.
- Tea tips versus larger leaves: Tea tips usually contains slightly more caffeine than larger leaves. However, it still hard to say what amount ends up in your cup since tea tips are usually less oxidized, which brings us to the next topic.
- Oxidation level: less oxidized teas usually release less caffeine. Though it’s true that tea tips contain more caffeine, they usually in the end release less caffeine because they are usually less oxidized (e.g. silver needle tea and dragon well tea)
- Processing: the more dense the tea becomes after processing the slower it will release caffeine. Take for instance jasmine dragon pearls. Because they are curled into pearls, it will release it’s caffeine more slowly.
- Steeping step: the first steep will release more caffeine than the steeps after. In China, most people will rinse the leaves for a few seconds before steeping. The question is whether researchers should take practice this into account when setting up their research.
Given all the factors above, we could say that ‘tea type’ is just one of the factors that could be added to the list above. Still, I do believe that we can still generally assume that green tea does contain less caffeine than black tea.