The caffeine content in coffee has always been a subject of interest. Coffee is the biggest dietary source of caffeine and its consumption can have an impact on your health. For avid coffee drinkers, watching their caffeine intake is certainly important.
The average cup of coffee has about 95mg of caffeine.
However, that is half the picture and doesn’t take into consideration the various factors that affect caffeine content. For example, caffeine in espresso is another important metric. Popular beverages like latte, cappuccino, mocha, and many more are based on espresso.
Similarly, the “average” 8 oz cup of drip coffee can have 95-200 mg of caffeine content. In some cases, the caffeine content can go above 500mg.
As you see, the numbers are nuanced. The caffeine content of your cup of coffee depends on several factors. It’s important to consider them and see how they might be relevant to you. Let’s get some specifics to understand how your coffee and caffeine content get along.
Your Preferred Coffee Beverage Matters
Often, when someone quotes the caffeine content of coffee, they’re considering drip coffee. But that’s not the only type of coffee available and is therefore not an exhaustive number. The caffeine in espresso matters.
As already noted, espresso is the base of several popular beverages. So while your macchiato, latte, or cappuccino have a different texture and taste, their caffeine content is essentially the same as espresso. Often, a single shot of espresso goes into making these beverages, though a double shot isn’t a rarity either.
Generally speaking, an ounce of espresso has 60-65 mg caffeine. A shot of espresso is often 1-1.25 oz. That way, you can expect your espresso-based beverage around 65 mg caffeine. Take that to 130 mg if your brew got a double shot of espresso.
A French Press (or plunger) brewed coffee has 80-140 mg caffeine. Brewing coffee with a percolator can get you 80-250 mg caffeine for an 8 oz cup.
A similar serving of instant coffee falls into the range of 30-90 mg caffeine.
Coffee Brewing Factors That Affect Caffeine Content
Caffeine content can vary widely with several additional factors. Here’s a quick look:
Variety Of The Coffee Plant
The coffee plant has several varieties, but the most notable for coffee consumers are arabica and robusta. The arabica plant is known to have a milder touch and has more flavorful beans. The variety of flavors and taste notes makes arabica the favored choice for consumers. Most gourmet coffees hail from arabica beans.
Robusta beans have a higher caffeine content than arabica. However, they lack the variety of nuanced flavors in arabica and tend to taste bitter when brewed. When sold for consumer use, robusta beans are blended with arabica beans for flavors that are easier on the palate.
While these beans affect the caffeine content, they don’t bring a massive change by themselves.
The Coffee Roast Conundrum
Does the coffee roast affect caffeine content? Well, that depends on who you ask, and everyone’s certain on their belief! Here’s how the various arguments on this topic lie:
- Coffee roast doesn’t affect the overall caffeine content of the brew
- Longer roasting periods cause heat to “burn” caffeine in beans, so light roast beans have more caffeine than dark roasts
- Dark roast beans have lower moisture and are thus lighter than light roasts. As such, they have more caffeine by weight (i.e. one pound of dark roast has more caffeine than a pound of light roast coffee)
The side you pick in this debate is up to you. However, it is safe to say that the change isn’t large enough to give any side a clear victory.
The Grind Size Of The Coffee
Coffee preparation and related specifics usually make the biggest impact on the caffeine content of the resulting brew. The grind size of the coffee is one of the more important metrics.
Simply put, a small grind size gives coffee grounds a larger contact area with the water. This allows higher extraction and thus greater caffeine content for your brew.
As we see from the numbers here, the caffeine in espresso is roughly 64 mg per oz. An 8 oz cup of drip coffee can have 95-200 mg caffeine. Clearly, the espresso shot has more caffeine by volume, even though the cup of drip coffee has a higher caffeine content by absolute numbers.
For comparison, espresso is brewed using finely ground coffee. Other brews, like drip coffee, French press, and filter coffee prefer medium to medium-coarse grind for their beans.
Contact Time And Temperature
The water temperature for the best extraction from coffee is 195-205 °F. This is slightly below the boiling temperature of water (212 °F). The longer you allow the water and coffee grounds to be in contact, the higher is the extraction and caffeine content.
Most processes don’t allow prolonged contact. An espresso shot, for example, is done in 20-30 seconds. The longest contact time belongs to French press, which might easily take 5 minutes.
The (Extra) Caffeinated Brew
Some commercially available coffee products have a touch of extra caffeine to be stronger and can be highly caffeinated. Death Wish Coffee is perhaps the best known in this type of coffee. It can push above 500 mg caffeine per 8oz cup of brewed coffee.
Coffee shops and chains usually have higher caffeine content in their brews. For example, Starbucks 8 oz can have 180 mg caffeine, while a Dunkin Donuts 10 oz cup can go to 215 mg caffeine.
Bringing It All Together
The caffeine numbers vary depending on several factors that contributed to brewing the coffee. But there are some fair estimates the consumer can make without going in too deep on the numbers. It is a fairly safe bet to consider the caffeine in espresso to be at 64mg per oz.
Drip or filter coffee’s caffeine levels can vary more widely. You can consider an average 8 oz cup to have 95 mg of caffeine. Keep in mind, the FDA-recommended limit for daily caffeine intake is 400 mg, so tamper your coffee intake to stay safely below these levels.