I’ve often wondered how much caffeine there is in an espresso shot. It pays to be informed about how much of a drug you’re putting in your body, especially when you drink as much as I do!
So how much caffeine is there in one espresso shot?
The caffeine content of espresso can vary considerably, but a good rule of thumb is to assume around 75mg for a single espresso shot and 150mg for a double espresso shot.
It’s also worth pointing out that it’s pretty rare to get only a single shot, even if you order straight espreso. And your cappuccinos and lattes and everything else are typically made with a double shot.
If you order your coffee ‘large’ or ‘strong’ then there’s a good chance the barista will use 3 or 4 shots in which case you can simply ask them how many shots they are using to get a good idea of the amount of caffeine you are drinking.
If you’d like to see how I arrived at those figures then keep reading. I can assure you the process was most scientific!
Amount Of Caffeine In An Espresso Shot
The first thing to point out is that the amount of caffeine in any drink or in any espresso shot is not constant. There are multiple variables that can affect how much caffeine ends up in your drink so we have to accept that any value is an estimate at best.
There are studies that support this and show that ranges of 25-214mg of caffeine per cup and 15-254mg per cup. It was even observed that a chain like Starbucks where you would expect consistency can give differences in caffeine in their espresso from 63-91mg of caffeine per cup in the same store!
We’re going to assume standard variables such as 14g for a double and 7g for a single and a coffee bean blend that is 100% Arabica (more on that later).
Now looking at the science behind caffeine in coffee, this website shows that caffeine makes up 1.2% of the mass of coffee beans. So during a full brew we can expect to extract most of that, if not all of it. I’ll assume 90% will be extracted.
This means that doing the maths, a 7g single espresso shot will have 7*0.012*0.9 = 75.6mg of caffeine and a 14g double espresso shot will have 14*0.012*0.9 = 151.2mg of caffeine.
A quick scan of the internet seems to agree with these as rough figures that work as a general rule. They are not going to be accurate all of the time. And as I mentioned, the fact is that there is no hard and fast way to figure out the amount of caffeine in your espresso short of putting a lab coat on implementing some college-level chemistry.
What Variables Can Affect The Caffeine In Espresso?
So to find out the figure for the amount of caffeine in an espresso shot it’s good to look at some of the variables we will be working with. The following things can affect how much caffeine can be extracted from the beans and into the drink.
Amount of coffee used. A good rule of thumb in the espresso making world is to use 7g of coffee beans for a single shot of espresso and 14g of coffee beans for a double shot of espresso. Most portafilters where you put the ground coffee will be ‘full’ once you add 14g of coffee or so, so there isn’t much room for error on this one.
Type of coffee bean. The two main varieties of coffee, Arabica or Robusta, have some very different characteristics and one of those is caffeine content. The Robusta, which grows at a lower altitude and thus needs to be hardier and more resistant to bugs, contains nearly twice the amount of caffeine as Arabica.
Now, making coffee with pure Robusta is very rare in Western countries, despite being the norm in places like Vietnam. In the States the majority of coffee is sold as 100% Arabica or sometimes (particularly for espresso) as something like 90% Arabica to 10% Robusta.
Type of roast. It’s a common misconception that lighter roasts contain more caffeine due to the roasting process (which is essentially cooking the beans) ‘burning away’ the caffeine.
While this does happen to some extent, it is offset by other things that happen during the roast such as dark roasts containing less water. Pound for pound, darker roasts have very slightly more caffeine although the difference is negligible for this purpose of this article.
Extraction. When you brew your coffee and mix the coffee grounds with the hot water, many of the compounds from the coffee begin to be absorbed and dissolved into the water. This is what we call extraction. Caffeine is one of the compounds that extracts fairly quickly in the process.
I read a study that showed half of all the caffeine gets absorbed within the first few seconds when making a 3-4 minute brewed coffee (I’d link it but I can’t find where I read it, sorry!)
I also can’t find anywhere that states with much certainty how much caffeine in the coffee bean (which as I mentieond is about 1.2% of its mass) actually gets absorbed into the drink.
It’s safe to say that this amount could be variable, but I can’t find anything to help me find out how much.
How Does It Compare To Normal (Brewed) Coffee
The easiest way we have of comparing different caffeine quantities is to look at the weight of coffee that is used. (I’m told that there are methods where you can calculate the caffeine content in a liquid but it requires some chemistry knowhow and a few ingredients you probably don’t have!)
So the question really boils down to how much ground coffee beans you are using in your brewed coffee. Typically, 14g would be considered on the low end of what you would use for brewed coffee with a normal range being in the region of 15-25g where the upper limit is getting quite caffeinated.
A typical amount for a ‘big’ cup of brewed coffee is 180-200mg, which comes in a little higher than my estimate of the amount of coffee in a double shot of espresso.
If you’re buying brewed coffee at coffee shops then it becomes even more difficult, it’s hardly normal behaviour to ask your barista how many grams of coffee they are using! You can predictably rely that the brewed coffee will have more caffeine content than a normal double of espresso though.
In any case, I thought I’d write up a quick guide to the amount of caffeine you get with brewed coffee that depends on the size of the drink and also the brew strength ratio.
This is worked out by simpy measuring your coffee in grams and water in millilitres and finding the ratio of them. So 15g of coffee to 255ml of water is a 1:17 ratio.
This ratio is used to describe the strength of the drink and 1:12-1:18 is considered a normal range with 1:15 being pretty normal for a coffee.
WEAK (1:18 coffee water ratio)
8 fl.oz (237ml) – 114mg caffeine
12 fl. oz (355ml) – 171mg caffeine
16 fl. oz (473ml) – 228mg caffeine
20 fl. oz (591ml) – 284mg caffeine
NORMAL (1:15 coffee water ratio)
8 fl.oz (237ml) – 152mg caffeine
12 fl. oz (355ml) – 228mg caffeine
16 fl. oz (473ml) – 303mg caffeine
20 fl. oz (591ml) – 379mg caffeine
STRONG (1:12 coffee water ratio)
8 fl.oz (237ml) – 190mg caffeine
12 fl. oz (355ml) – 284mg caffeine
16 fl. oz (473ml) – 379mg caffeine
20 fl. oz (591ml) – 474mg caffeine
Note that some of these are on the high side, particularly when you’re drinking 20 fl. oz of coffee in one go! I’m sure you don’t need telling that amount of caffeine is not the best for your health…
How Does It Compare To Other Caffeinated Things
Here are a few other caffeinated products for comparison’s sake with info coming from here. Some of these you might find quite surprising… a 20 fl. oz bottle of diet coke is equivalent to a shot of espresso!
Coca Cola – 12 fl. oz (375ml) – 34mg caffeine
Diet Coke – 12 fl.oz (375ml) – 45.6mg caffeine
Coke Zero – 12 fl. oz (375ml) – 35mg caffeine
Mountain Dew – 12 fl. oz (375ml) – 54mg caffeine
Dark Chocolate – 1 oz (30g) – 20mg caffeine
Tea – 1 cup (1 teabag) – 30mg caffeine