We are often asked about how tea and coffee compare in terms of caffeine content. While caffeine isn’t necessarily harmful, too much can have adverse effects. This is why many of us monitor our caffeine intake.
Did you know, the average adult in the UK consumes 130mg of caffeine per day1? Yet few really understand the factors that affect how much caffeine ends up in your hot drink.
Spoiler alert: short of analysing each cupful in a lab, it’s impossible to say exactly how much caffeine either tea or coffee contains. But don’t despair! By understanding the variables involved, it is possible to make an educated guess as to which of two drinks has the higher caffeine content.
Does that include tea vs coffee? Let’s find out!
What is Caffeine?
Caffeine is a bitter alkaloid that occurs naturally in plants. It’s also the most widely used psychoactive substance globally2! While lots of us are familiar with caffeine’s stimulative effects in humans, we don’t often think about its purpose in nature. A number of plants, including Camellia sinensis (tea), produce this compound as a natural pesticide. Buds and new leaves are most vulnerable to hungry insects, which is thought to be why caffeine is found in highest concentrations in these.
Caffeinated Beverages: Tea vs Coffee
According to researchers, coffee beans contain 1.1-2.2% caffeine, while Camellia sinensis plant (tea) leaves can contain three times these concentrations3.
However! It takes fewer tea leaves to make a cup of tea than ground coffee beans to make a cup of brewed coffee – around 5g tea leaves vs 10g coffee grounds. In addition, more caffeine is extracted from these grounds than from tea leaves, partly because of their greater surface area and partly because they’re (usually) brewed in hotter water.
The result: a higher concentration of caffeine in the coffee cup than in the teacup.
In the Average Cup
The average espresso shot contains 70-80 milligrams of caffeine4, while a standard cup of brewed coffee packs 160-170mg5. The recommended limit of caffeine intake for adults is 400-500mg6, so that’s around 3 cups or 5 shots of coffee a day.
Caffeine content in tea is trickier to pin down. Factors from the tea plant varietal, through leaf processing to brewing all play a role. Very generally speaking, a cup of tea contains around 10-60mg7 caffeine. That’s quite a few more cups of tea than coffee before you’re nearing the recommended caffeine levels. And while a cup of instant coffee contains less caffeine than brewed coffee, it still has more caffeine than a cup of tea.
So:
A cup of coffee does generally contain more caffeine than a cup of tea.
Is that a good thing or a bad thing? Let’s take a closer look at caffeine and its effects.
The Effects of Caffeine
Caffeine is a natural stimulant of the central nervous system8. It works its magic by blocking adenosine, a chemical in our nervous system that slows down brain activity and causes us to feel tired9. The result is more wakefulness, improved cognitive performance and relief from fatigue10.There are also some widely known adverse effects of caffeine consumption, such as tremors, anxiety and elevated blood pressure11.
Simply put: there can be pros and cons to caffeine consumption. However:
The effects of caffeine in tea and coffee differ.
This is due to other substances present in tea but absent from coffee, such as the amino acid L-theanine. Studies suggest this mood-boosting chemical enhances caffeine’s positive effects, such as increased alertness and concentration, while reducing adverse ones, such as anxiety12. Perhaps this is why tea drinking isn’t associated with ‘the jitters’.
Is Caffeine Bad for You?
Caffeine gets a bad rap, but is that fair? True, it is an addictive substance and too much caffeine can lead to issues such as those mentioned above. At a dose of 10000mg, caffeine can actually prove lethal13. Rest assured this isn’t a risk for the average tea drinker – you’d have to consume well over 160 cups of tea in a day!
In fact, studies suggest caffeine can help protect against coronary heart disease, Parkinson’s disease and some types of cancer14. As well as the health benefits, there are wellbeing benefits linked to the caffeine in tea. Many drinkers enjoy the sense of relaxed alertness thought to be a result of the interaction between caffeine and L-theanine.
Different Tea Types
The amount of caffeine present in tea varies between and within the main tea types (white, green, black, pu’er and oolong). Here are just some of the factors that define the tea type and affect caffeine content in tea leaves:
1. Plucking season
Possibly due to the increase in insect numbers, caffeine content tends to be higher in summer-picked leaves.
2. Varietal of Camellia sinensis (Camellia sinensis sinensis vs Camellia sinensis assamica)
The assamica variety (commonly grown in northern India and Africa) generally contains more caffeine than sinensis plants.
3. Sun exposure
Tea leaves grown in shade, such as matcha green tea, often contain more caffeine than their non-shade grown counterparts.
4. Processing
A longer withering (moisture evaporation) stage can increase caffeine content. A longer period of oxidation (allowing the leaves to brown) can reduce it.
5. Leaf type
Teas made from buds and new leaves are likely to contain more caffeine than tea that uses older growth and stems.
The Brewing Process
Generally,- The more leaves you use;
- The longer the steeping time;
- The hotter the water;
The higher the caffeine concentration in your cup of tea.
Controlling the amount of caffeine in your cup is therefore about the tea you choose and the way you brew it. For example, although white teas use new growth (usually higher in caffeine), pickers pluck the buds/leaves in spring (rather than summer). You brew white tea relatively briefly, in sub-boiling water. Carefully brewed white tea is therefore often a great low-caffeine option.
Black Tea vs Coffee
While black teas often score highly for caffeine compared to some other tea types, the average cup of black tea contains around half the caffeine of the average cup of brewed coffee.15
Green Tea vs Coffee
Green tea is sometimes thought of as low in caffeine. This is often true, mostly due to the fact that green tea is brewed with sub-boiling water.
However, in the case of matcha green tea, the leaves themselves are consumed (as a dissolved powder), meaning it has a relatively high caffeine content. Matcha can contain the same amount of caffeine as a shot of espresso.
Rooibos vs Coffee
Rooibos plants are naturally caffeine-free, so if you’re looking to reduce your caffeine intake, a full-bodied cup of rooibos beats coffee hands down!
Herbal Tea vs Coffee
Most herbal teas contain no caffeine either: a good choice for a pre-bedtime drink.
Which Hot Drink is Better for You?
Another question without a simple answer! A caffeine-sensitive someone in need of a good night’s sleep might find herbal tea, such as Night Sky Calm - soothing with lavender and lemon balm - best. For someone seeking the energy of a caffeine hit but without the ‘shakes’ associated with coffee, a robust cup of L-theanine rich Assam might be just the ticket.
Caffeine Free Options
Drinking tea and coffee doesn’t have to involve caffeine, you can get decaffeinated tea and coffee or there are plenty of herbal teas which are completely caffeine free. Green teas also contain less caffeine than standard tea bags.
Do you keep an eye on your caffeine consumption? Let us know over on Social, we’d love to hear! #PressPause #DragonflyTea
Sources
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Assessing caffeine intake in the United Kingdom diet https://pubmed.ncbi.nlm.nih.gov/23601385/
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Caffeine is the world’s most widely used psychoactive substance https://pubmed.ncbi.nlm.nih.gov/9889511/#:~:text=Caffeine%20is%20the%20most%20widely,an%20effect%20on%20the%20brain.
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January 2009 Czech Journal of Food Sciences https://www.researchgate.net/publication/258451908_Determination_of_Caffeine_Content_in_Tea_and_Mate_Tea_by_Using_Different_Methods
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Caffeine informer espresso https://www.caffeineinformer.com/caffeine-content/espresso
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Caffeine informer coffee https://www.caffeineinformer.com/caffeine-content/coffee-brewed#:~:text=Coffee%20(brewed)%20contains%2020.38%20mg,of%20163%20mg%20of%20caffeine.
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EFSA Caffeine guidelines https://www.efsa.europa.eu/sites/default/files/corporate_publications/files/efsaexplainscaffeine150527.pdf
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Caffeine informer tea https://www.caffeineinformer.com/the-caffeine-database
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Caffeine common stimulant https://pubmed.ncbi.nlm.nih.gov/9889511/#:~:text=Caffeine%20is%20the%20most%20widely,an%20effect%20on%20the%20brain.
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Adenosine https://thebrain.mcgill.ca/flash/i/i_03/i_03_m/i_03_m_par/i_03_m_par_cafeine.html
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Caffeine stimulant effects https://www.ncbi.nlm.nih.gov/books/NBK223808/
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Caffeine adverse effects https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4462044/
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L-theanine https://apjcn.nhri.org.tw/server/APJCN/17%20Suppl%201/167.pdf
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Fatal dose https://pubmed.ncbi.nlm.nih.gov/20096021/
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Caffeine side effects https://zellavie.ch/wp-content/uploads/2020/06/Annual-Review-of-Nutrition-2017.pdf
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Black tea vs coffee https://www.bbcgoodfood.com/howto/guide/how-much-caffeine-tea#:~:text=Does%20black%20tea%20have%20more,average%20of%2095mg%20per%20cup.
