DISCLAIMER: This blog is a discussion and opinion piece on caffeine, and should not be taken as health advice or verified scientific truth on the matter. Please consult a doctor for medical advice regarding caffeine.
Ah, caffeine, the kick of life to start the day and crack on with the daily grind. The thought of starting the day without a cup can seem preposterious in this faced paced day and age. How would we mentally function without the alert mental energy for the tasks ahead? We can start the day with a double or single espresso, black americano, maybe a latte? but the quantity of caffeine can vary by a modest chunk. And depending on the individual and how sensitive they are to caffeine, this can come as quite a shock when the buzz is under or overwhelming. Let's explore this phenomenon fueling the modern working world.
What is caffeine?
Caffeine is a chemical compound, which in chemistry terms is 1,3,7 trimethylxanthine. In its isolated form, caffeine is a bitter white powder, and absorbed into the bloodstream with peak levels around 30 minutes to 2 hours after consumption. Plants produce caffeine primarily as a pesticide against herbivorous insects, this may explain caffeine as a evolutionary survival mechanism.
Regarding how caffeine affects the body, caffeine combats fatigue and tiredness by blocking a chemical called adenosine from reaching adenosine receptors. In addition, caffeine causes the body to increase dopamine production. A hell of a combo! Unfortunately caffeine is renowned for coming with a crash in energy, and a wave of fatigue, and the adenosine mechanism of adenosine coming back in full force to those receptors may explain the fatigue.
Whilst feeling of alertness, and high energy may come from drinking caffeine, the opposite may be true. Caffeine withdrawal is known to have symptoms like low energy, poor memory and headaches, so a daily dose of caffeine may be withdrawal relief. After all is said and done on positive and negative effects of caffeine, its a highly subjective area depending on the individual, with some far more sensitive to caffeine than others.
Beyond this, caffeine was first popularised thousands of years ago from tea consumption, and only around the 16th century did caffeine gain a foothold through coffee consumption. In the past 100 years caffeine has become ubiquitos with soft drinks, energy drinks, and food products aiming to act with stimulant and/or energy producing properties. Compounds like sugar and L-Theanine can all affect how caffeine acts in the body.
How much caffeine is in coffee?
There is no fixed amount of caffeine in a cup of coffee, given this can vary due to a number of factors. Harvard health outlines that '8 ounces of brewed coffee contains about 95 mg caffeine' - https://www.hsph.harvard.edu/nutritionsource/caffeine/. But this number truly is arbitrary. And the final number depends on the variety of coffee, roast profile, ratio of coffee to water, and brewing method.
Starting with variety, robusta coffee, the most commonly grown and drunk variety of coffee for commodity is 2.2% caffeine, whilst an arabica bean has 1.2% caffeine - CoffeeChemistry.com. On caffeine informer, a filter or drip 8 ounce cup of robusta coffee can have as much as 265 mg of caffeine! Quite the difference between the 95mg stated from Harvard Health.
Regarding roast profile, there's a great deal of misinformation and myths regarding whether dark roasts have more or less caffeine that lighter roasts. For clarity on the issue, it's worth addressing common confusion looking at caffeine from weight vs volume. The better practical reasons for measuring caffeine by weight comes from almost all coffee related recipes calling for coffee by weight whether its espresso, french press or V60. According to a mecially reviewed article on healthline.com, 'If you’re comparing light and dark roast coffee by weight, the caffeine amount is comparable, with only a slightly higher caffeine amount in a lighter roast'. In terms of volume, the same answer applies with higher caffeine in the lighter roast.
The bitterness in coffee comes predominantly from caffeine! Roasting a coffee darker to some extent increases bitterness due to caramelisation of sugars breaking down, meaning less sweetness and a more pronounced bitter taste. Additionally, commodity robusta coffee has twice the amount of caffeine as arabica, and therefore more bitterness.
Caffeine from energy drinks, chocolate, green tea?
Caffeine has been adapted and commoditised for a variety of purposes whether its a quick energy boost, relaxing leisure food or for sustained focus and productivity. With regards to energy drinks, caffeine is isolated and added as the main ingredient to increase a sudden jolt of alertness and energy. Other ingredients for this purpose include b-vitamins, sugar, taurine and ginseng.
Chocolate contains a small amount of caffeine, and other compounds such as theobromine which is known to act as a stimulant; possibly increasing heart rate, alertness and urination - https://draxe.com/nutrition/theobromine-benefits/.
Green tea, especially of the matcha variety, contains a moderate amount of caffeine, with other compounds such as L-Theanine. This amino acid is associated with reduced stress and anxiety. Healthline.com writes 'In a review of five randomized controlled trials that included 104 participants, four trials linked L-theanine with reduced stress and anxiety in people experiencing stressful situations'
Coffee can contain anywhere in the ballpark of 95 to 265mg of caffeine, and this depends on such a wide variety of factors like genetic variety of bean, roast profile and brew methods. The most major factor being whether the coffee is arabica or robusta. If your concerned about caffeine levels in coffee, you may want to check whether what your drinking is arabica or robusta! Remember that coffee has many other compounds that may effect energy levels, focus, and productivity, so it's worth bearing in mind that caffeine is one piece of the puzzle.