A steaming cup of coffee and roasted coffee beans on a burlap mat

Caffeine: Setting the Record Straight

Author: David Kelley
Steaming cup of coffee with roasted coffee beans on a burlap mat
There is a lot of misinformation floating around about caffeine and coffee. Here we hope to clear things up.

If you’re like most people, caffeine makes your world go round.

And if you’re like most people you probably also have no clue as to how much caffeine is in your grande latte from Starbucks or your morning cup of automated drip coffee. All you know is that after a cupor threeyou’ll be ready to function like a normal, productive human being. 

So, what exactly is caffeine, and how much of it is in your coffee? 

Let’s find out.

Caffeine 101

Caffeine is a naturally occurring chemical compound that acts as a stimulant. Chemically speaking, caffeine is an alkaloid—which essentially means it has a nitrogen base. What this means for plants on a biological level is still largely unknown, but for us humans, we know it means increased attention and alertness. 

While caffeine is most naturally associated with coffee, tea, and cocoa, it actually exists within roughly 60 different plant species. For example, guarana berries, kola nuts, yerba maté, guayusa, and yaupon holly are just some of the natural sources where caffeine can be found. 

In case you’re wondering what caffeine looks like but can only picture coffee beans, it’s simply a white crystalline powder with a very bitter taste when broken down into its purest form. This is what gets added to your sugary sodas and energy drinks, as well as diet aids and some medications. 

In terms of being a natural stimulant, caffeine acts as an adenosine receptor antagonist. Adenosine is an inhibitory neurotransmitter, which ultimately means it acts as a central nervous system depressant. 

Under normal conditions, adenosine promotes drowsiness which helps us fall asleep. 

Being an adenosine receptor antagonist, caffeine works by acting as an adenosine imposter. In other words, it binds to the cell receptors in your brain and blocks the adenosine from taking action, which results in a nice energy boost. 

Interestingly enough, since caffeine has this effect on the brain, it’s considered to be a psychoactive drug—which makes it the most widely used, legal, and FDA-approved drug known to man.

How Much Caffeine Is in My Coffee?

Women carrying two large coffee drinks in her arm

When it comes to caffeine content and coffee, it's all about the volume.


When it comes to caffeine and coffee, the average cup contains between 75 and 100 milligrams of caffeine. 

How much caffeine you’re actually consuming per day depends on how many “cups” you order or pour yourself as well as the type of coffee you drink. Since the term cup of coffee can be pretty subjective in its relation to size, we’ll be breaking down the caffeine ratio by the ounce. 

However, before we get to the milligrams per ounces, it’s important to understand that there are a few scores to settle in the world of caffeine and coffee:

The Bean Type 

Caffeine begins with the bean—and there are two main types of coffee plant species. 

These two plants produce the commonly recognized Arabica beans and the lesser known Robusta beans. 

Arabica beans are generally regarded as the higher quality coffee beans as they’re on the sweeter and smoother side. Robusta, on the other hand, are easier to cultivate but produce a stronger and more bitter flavor profile.   While Arabica beans are more popular, especially among craft coffee roasters, Robusta beans have twice the amount of caffeine. They’re also more commonly found in your cheaper and more generic brands of coffee on supermarket shelves.


Light Roast Vs. Dark Roast Vs. Espresso

There’s a common misconception that the darker the roast, the more caffeine there is. This is especially true when espresso coffee enters the mix.   However, bean for bean, all roasts have roughly the same amount of caffeine.   Of course, when the beans are roasted, they tend to lose some of their mass, which means that pound for pound, a bag of dark roast beans will contain a slightly less amount of caffeine compared to its light roast counterpart.   Now, when we talk about espresso, we’re talking about the extraction method used to make one tiny cup of joy.   While many people think that the term espresso also refers to the roast, in reality, there is no “espresso roast.” It’s medium to medium-dark roasted beans that are typically used to make an espresso.   Which brings us to our next point:

It’s All About the Volume

When coffee is brewed, it’s measured by volume—with a specified coffee scoop. 

This is also where it becomes a bit more complicated, so bear with us. 

In terms of volume, a light roast cup of coffee will contain more caffeine compared to a dark roast cup. 

Why? Because the lighter the roast, the less mass is lost, which means the beans are heavier and denser—which means they contain more caffeine. 

However, if you measure by weight rather than volume (mass) the dark roast beans will have more caffeine, simply because they are less dense and therefore require more beans to achieve the same weight. 

This is precisely why espresso is associated with a straight shot of caffeine—because the extraction method is performed by using an immense amount of pressure with a greater volume of coffee. The result is a denser cup with the addition of crema and rich oils to bring the body of the beverage full circle. 

So, how much caffeine are you really drinking? Let’s take a look at the serving size to caffeine ratio based on coffee type:


Coffee type

Serving Size

Caffeine Per Ounce

Brewed Coffee

8 fl oz

 11.88 mg

Drip Coffee

8 fl oz

8.13-15 mg

Decaf Coffee (brewed)

8 fl oz

0.38-0.5 mg

Decaf Coffee (instant)

8 fl oz

0.25-0.38 mg

Cold Brew Coffee

16 fl oz

12.5 mg

Nitro Brew Coffee

16 fl oz

20.31 mg


2 fl oz

30-51.34 mg

Highly-Caffeinated  Coffee Brands

12 fl oz

58.5-77.33 mg


So, if you wanted to know how much caffeine was in your venti mocha latte from Starbucks—based on this chart*—you would look at the serving size, which is 20 ounces and the type of coffee used, which is espresso and calculate from there. 

Keep in mind that for beverages involving espresso and milk, the amount of espresso you get only increases if you order an extra shot. 

So, your 20 oz mocha latte would still only contain one shot of espresso, which is equivalent to 2 fl oz—which means you’re getting anywhere between 30 and 51.34 mg of caffeine per ounce of espresso. So, you would essentially be getting between 60 and 102.68 mg of caffeine for that one shot (2 fl oz) of espresso even though the drink is 20 fl ounces.

Of course, if you’re ordering a regular coffee in the venti size, you’re getting roughly 20 ounces of brewed coffee—which would equate to about 230 mgs of caffeine. 

Of note is the fact that Starbucks coffees are actually known to contain more caffeine compared to your basic brews as they offer a variety of specialty roasts and more. You can check out their menu online to see the actual caffeine amount per beverage. 

Remember to always drink your coffee in moderation—and, life is short, so steer clear of the cheap stuff!


Be sure to shop Two Bit Rush Coffee Roasters' coffees. We offer a selection of single origin coffees, curated blends, and flavored coffees. Roasted daily and delivered fresh.

link button to Two Bit Rush Coffee Roasters beans 









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