How Much Caffeine in a Shot of Espresso? Authorities Weigh In

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how much caffeine in a shot of espresso

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Caffeine content has been a hot topic for me lately, so why not keep up the trend, cover other favored brews, and make it a proper series? And since we brushed on it when discussing Starbucks’ blonde roast, it seems as good a time as any to dive into espressos.

I’d love to tell you that the answer you’re looking for is simple, but what is in this world?

What I can tell you is that the general consensus among experts is that a single shot of espresso contains 64 mg of caffeine.

But the fact that there’s a consensus means only some agree. So, in the spirit of transparency, let’s examine all sides of this particular cup of crema.

What is Espresso?

If you aren’t entirely new to this finely ground and pressurized brew, feel free to skip ahead. Or hey, keep reading and give yourself a refresher.

what is espresso caffeine content
Making espresso is a surefire way to get the most caffeine from each and every bean.

Espresso is a caffeinated beverage that pulls a more full-bodied taste, in flavor and caffeine, through a brewing process that utilizes a high-temperature and high-pressure extraction.

Brewing the perfect shot of espresso comes down to personal preference and the varying factors that bring all the ingredients together.

What Factors Affect Caffeine Content?

Several variables may influence how much caffeine exists in your espresso, but not all can be proven beyond a shadow of a doubt.

The five factors that have proven to affect caffeine content in a brew are the bean’s species, the water’s temperature, the coffee-to-water ratio, the volume of the coffee drink, and the type of fertilizers used when growing.

Each of these factors will positively or negatively affect the caffeine content in your shot of espresso. To understand how and what other contributors might do the same, look at the data pulled from a 2021 medical review.

Contributing FactorImpactful?Notes
Brew TimeProbableMay Contribute, but Effect Is Minimal
Coffee Bean OriginProbableMay Contribute, but Effect Is Minimal
Coffee-To-Water RatioYesThe Ultimate Factor
Exposure to LightProbableShade Positively Impacts Caffeine, but Likely Tied to Species
Grind DegreeInconclusiveEffects Taste, Not Caffeine
Grow MethodYesNitrogen Fertilizer Has Shown to Increase Caffeine Content
Height Above Sea LevelProbableWill Effect Arabica Beans. No Evidence to Support Robusta
RoastingInconclusiveLonger Roasting May Decrease Caffeine, but No Supporting Evidence
SpeciesYesRobusta Has Double the Caffeine than Arabica
Storage of BeansProbableMay Contribute, but Effect Is Minimal
Volume of Coffee DrinkYesVolume Directly Correlates to Caffeine Content
Water PressureInconclusiveMay Contribute, but Effect Is Minimal
Water TemperatureYesLower Temperature Will Reduce the Caffeine Extracted
Water TypeInconclusiveEffects Taste, Not Caffeine

With all these factors taking part in how caffeinated your espresso is, how are you supposed to know what you are drinking?

The best way to figure that out is to ask people much smarter than me. Bring on the experts!

How Much Caffeine in an Espresso Shot?

According to the leading authorities analyzing caffeine content, a 1-ounce (30 mL) espresso contains 64 mg of caffeine.

Both the USDA and Mayo Clinic agree on this estimation. So what about the variance? What experts are going against the grain?

For one, the Harvard School of Public Health reports that a shot of espresso has 65 mg of caffeine. Not too far off, right? Well, the difference here is that Harvard suggests that a single shot of espresso is 1.5 ounces instead of 1 ounce.

how much caffeine in an espresso shot
The average amount of caffeine in an espresso is 64 mg.

Technically speaking, many espresso lovers consider a shot to be within that broader range, so let’s roll with it and move on. But how about another example? The EFSA, or the European Food Safety Authority, is the overseas equivalent of the USDA.

A UK survey by the EFSA successfully compiled data on caffeine concentrations from varying sources, specifically 400 samples of teas and coffees. The combination of actual espresso samples in addition to their database of 66,531 previous survey participants, the EFSA determined that a standard espresso of only 60 ml contained as much as 80 mg of caffeine.

So Europeans showed to have smaller shots but more caffeine?

You bet! It makes sense when considering the difference between American and European espresso, at least regarding the amount of caffeine. 

american vs european espresso
The caffeine content won’t usually match up when comparing espresso from the US and most European countries.

While Americans enjoy a dark roasted espresso, most establishments use arabica beans to get the enticing taste and aroma we’re used to. Traditional Italian cafes stick to robusta coffee beans which have double the amount of caffeine. So if you have any pending trips overseas, know what kind of brew you’re getting. 

Oh, a quick FYI; if you order a coffee in Italy, you’re going to get an espresso.

Lastly, let’s look at two more US authorities in the caffeine industry: Starbucks and Dunkin Donuts.

Now, some coffee snobs may be rolling their eyes right now, but it’s a proven fact that almost half of American coffee drinkers buy their coffee from quick-service cafes like this.

A single shot of espresso from Starbucks has 75 mg of caffeine, slightly more than the average in an American brew considering their Solo shot is only 0.75 ounces. 

Starbucks solo shot
Starbucks and Dunkin Donuts have higher caffeine content in their single-shot espressos than the national average.

When you order a Dunkin Donuts single shot espresso, you get a whopping 2-ounce shot with 118 mg of caffeine. That is 59 mg per ounce, which wouldn’t be a lot, except Dunkin’s single shot is the size of a traditional double shot.

As you can see, there can be a lot of variances when it comes to caffeine in espresso. Besides the brew method, where the bean comes from, and other factors already laid out, you also have to worry about how your barista measures their shot.

FAQs About Caffeine in a Shot of Espresso

I’m always glad when I can solve the riddle you’ve been stumped with. But before you head out, I might have solutions to other espresso questions that slipped your mind. So keep reading and find out.

Is Light Roast Good for Espresso?

Light roasts aren’t good or bad for espresso. But the more popular roast for espresso, at least in the US, is a medium roast. 

is light roast good for espresso
A light roast can make a good espresso, but it usually depends on preference.

The good thing about espresso is that the flavor won’t always be the same. The many factors in charge of your finished product can change slightly each time you make a shot. Not to mention that many home baristas use a blend of light and dark roasts to experiment with different tastes.

If you prefer a lightly roasted coffee, then a similar espresso will be a good option. But don’t be afraid to try new things!

Is Blonde Espresso Stronger?

Blonde espresso is brewed from lightly roasted coffee beans which some say are stronger because of their higher caffeine content than darker roasts.

is blonde espresso stronger
It’s such a loaded question. What do you consider stronger to be?

Making espresso will extract the caffeine and flavors from ground coffee using a pressurized method that delivers the coffee in a concentrated form. So its already higher caffeine content will taste even richer. 

Although, some coffee drinkers think a more robust espresso isn’t about the bitterness of potent caffeine but the natural flavors that generally come with a dark espresso. Simply meaning, the answer depends on the individual.

How Much is One Espresso Shot Compared to a Cup of Coffee?

A standard 8 oz cup of coffee has 96 mg of caffeine, which is 50% more than a 1 oz shot of espresso.

However, this is based on the accepted average caffeine content in the United States. When you compare the two using different data, the percentage will fluctuate slightly.

how much is one espresso shot compared to a cup of coffee
Like any good scientist, set your variables, and the math is simple.

If you’re considering the difference between decaf products, you will get entirely different totals. An 8 oz brewed cup of decaf coffee has 2 mg of caffeine, and a 1 oz decaf espresso has 0 mg of caffeine. 

The comparison shows a cup of coffee with only 2 mg more caffeine, but the formula changes when calculating between decaf and caffeinated.

How Many Shots of Espresso is Too Much?

The number of espresso shots considered too much by health professionals will vary depending on your age and current health, but the supported trend suggests 500 mg of caffeine in a day is too much. This translates to nearly 8 American espresso shots or 6 European shots of espresso.

how many shots of espresso is too much
Too many shots of espresso can have some dangerous side effects.

Again, this recommendation provided by Frontiers in Nutrition will change for each barista or cafe. When looking at the two larger US coffee chains, too much espresso would equate to 6 and a half Starbucks shots or 4 Dunkin Donuts shots.

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