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Is it true that espresso has less caffeine than regular coffee?
Yes and no. An espresso cup has about as much caffeine as a cup of strong coffee. But servings for espresso are much smaller. Which means that the content of caffeine per milliliter are much higher than with a regular brew. Moreover, caffeine is more quickly assimilated when taken in concentrated dosages, such as an espresso cup.
The myth of lower caffeine espresso comes comes from the fact that the darker roast beans used for espresso do have less caffeine than regularly roasted beans as roasting is supposed to break up or sublimate the caffeine in the beans (I have read this quote in research articles, but found no scientific studies supporting it. Anybody out there?).
One more thing that should be considered when comparing caffeine content of espresso is whether the beans are arabica or robusta. Robusta has about twice as much caffeine as arabica therefore a coffee blend starting with a large amount of robusta will have more caffeine regardless of prep method. Many (but not all) supermarket brands of coffee have a fair amount of robusta mixed into the blend to keep production costs low. Some espresso blends have between 4% and 12% robusta. The robusta is uses for a combination of reasons not least of which is flavor and better crema production. Many espresso blends have no robusta at all. For a good espresso blend price is not the reason for adding robusta and a good quality robusta is actually much more expensive than a cheap arabica bean and somewhere on par with a similar relative quality arabica.
Here's the caffeine content of Drip/Espresso/Brewed Coffee:
Drip 115-175 (7 oz cup) Espresso 100 1 serving (1-2oz) Brewed 80-135 (7 oz cup)
Obviously these numbers are estimates at best.
Comments
Minor confusion ....
This is copied from your article above (2nd para):
Robusta has about twice as much caffeine as robusta ..... :-)
George
robusta has twice as much as
robusta has twice as much as arabica
caffeine content of coffee
are those numers suppose to be mg./ oz? It looks like the espresso is and the other 2 are mg./8 or 12 oz cup. Can you clarify please.
Also I have read a long string of answers and questions. I would like to add to it:
Much of the information that follows I gleaned from detailed discussions with the owners and brew masters of Java Cofee and Tea Co. They have a shop in Houston for 30 years at least and a website. Each coffee is graded by acidity and mild-bold flavor. Between them, my nurse's training which includes chemistry, and experience with coffee over the years, this is some information I have obtained:
From my understanding of the chemistry of caffeine, it does not evaporate. Instead it is the acidty in the coffee that destroys the caffeine over time. Anyone who brews tea knows that tannic acid in the tea destroys the caffine, right? so you try to brew it to reduce the tannic acid production which enhances the caffeine content. Also the flavor and drinkability of the brew for those of us who have sensitive stomachs, as the taste of tannic acid is harsh. The lower acid coffees therefore generally have more caffeine, better taste, If you ask me. I have acid reflux and acidic coffee really upsets my stomach. So I have a built in acid barometer, lol. Coffee that sits on the heat definitely becomes more acidic, harsher tasting and the caffeine might become more concentrated too if the acid were not destroying it. But saving coffee at room temperature does not necessarily lose the caffeine if you have a low acid coffee. I believe Robusto beans also have much higher acidic content than most arabica, giving it less refined taste and destroying some of that extra caffeine. Another source of destroyng the caffene is in the roasting process. What degree heat are the beans at when roasting? My impression of Starbucks Coffee beans are generally roasted fast at higher heat, making them very dark and for my taste, burnt tasting and lacking in caffeine. I work nights and I need decent amounts of caffeine to make it, lol.
* reply
RE: caffeine content of coffee
I can't confirm or deny your claims about acidity and affeine. I have not seen any research that indicates this is the case but I can't say I have seen anything to the contrary.
Do remember when talking about coffee acidity does not refer to the ph of the coffee but to a taste profile. Think of wine not chemistry for this. Of course the ph also affects the flavor profile.
Fast vs slow roasting both have their proponents. I'm not really sure what method Starbucks uses. They are big enough I would guess they would want to roast as fast as they can while still retaining their flavor profile. In my experience a faster air roast will leave more high flavor notes than a slower drum/convection roast at the same roast level but I can roast lighter with a slower drum roast and still get a good flavor profile with plenty of high notes ithout having the burnt notes I get in a faster roast. Having said all that too slow a roast is baking not roasting.
One thing you might try if you want to reduce acidity (flavor and ph) is using a paper filters. That will also remove some flavor. I believe Kenneth Davids mentions this in one of his books.
Espresso caffeine content
I cannot point to definitive research you probably have not already located regarding this "dark roasting sublimates caffeine" topic. The many books in my coffee library perpetuate this myth without citing supporting scholarship although Corby Kummer cites the caffeine chapter of "Psychiatry/Diagnostic and Statistical Manual" 4th ed, 1994. However, there is one factor you might consider including in your discussion about espresso. Robusta beans contain twice as much caffeine as arabica beans. Most supermarket and office coffees are primarily cheap, caffeine-riddled robustas from Brazil. The better espresso blends are almost all 100% arabicas. The exceptions are the so-called northern Italian style espressos which contain 4-12% high-quality robustas to add color, body, crema, and distinctive flavor profiles. See Josuma and Espresso Vivace.
http://www.josuma.com/european.shtml
http://www.espressovivace.com/blends.html
cited works:
Illy, Francesco & Riccardo. "The Book of Coffee" Abbeville Press, 1989. See page 14 for comparison of robusta and arabica caffeine content. See page 175 for descriptions of espresso blends.
Davids, Kenneth. "Espresso: Ultimate Coffee" Cole Group, 1993. See page 50 for the "caffeine goes up the chimney" myth about dark roasting.
Kummer, Corby, "The Joy of Coffee" Chapters, 1995. See page 163 for everything caffeine-ish.
david bogie
My claim to fame: "FAQ: Home Espresso Machines" as seen 1987-1994 on the pre-Web Usenet newsgroup alt.coffee
re: Espresso caffeine content
Welcome David.
Sounds about right.
I do want to make a comment on a very fine point. You said: "Most supermarket and office coffees are primarily cheap, caffeine-riddled robustas from Brazil." In the last handful of years the robusta vs. arabica distinction has hit middle America and many supermarket coffees are now 100% arabica. It's still cheap garbage coffee but it is cheap arabica garbage coffee. I think it's a good selling point when all a person knows is "arabica = good".
As a side note the worse of the robusta actually comes from Vietnam and not Brazil. At least with Brazil there is some high quality arabica coming out of the country. Vietnam is pretty much a coffee wasteland as far as I can tell.
Thanks for the comments. They are right on the head and worth a modification to the main article.
Loss of caffeine: Clarification request...A few questions...
Hi,
If one filters the coffee, through a paper filter or cloth for example -- like straining, in other words -- does the resultant brew contain less caffeine?
It *seems* to make it less-strong, seeing as the oils get filtered out (?? I assume) -- is this so?
Is filtered/strained coffee less caffeinated?
Also, no one seems to have answered the question of loss of POTENCY, answering the question of flavor loss in its stead: Does coffee, before brewing actually lose caffeine over time? I've never heard that before.
And does it lose caffeine any other way? By "evaporation," as someone mentioned...sounds odd.
Anyone know?
caffeine
The espresso companies all claim that when brewing espresso, cappuccino etc. The vacuum pump system actually extracts most of the caffeine leaving the espresso with a much lower content then a cup of regular coffee. They claim that one espresso contains less caffeine then 2 strong cups of coffee.
hmmmmmmmm thumbs up for espresso!
Lose Caffeine over time?
Well, I was looking for any conclusive evidence on the subject as my in-laws claim they can have coffee after 1 hour because all of the caffeine is gone...
This of course contradicts my Organic Chemistry training. Water's boiling point is 212 F, Caffeine's is about 313 F.... water evaporates first. The coffee never reaches 313 F, or the coffee would be boiling.
Since the water evaporates first, that only leaves more caffeine, meaning that it actually gets stronger over time.
However they insist it gets weaker so I wanted to verify. 1 year of O-Chem tells me it gets stronger over time, but I could be wrong which is why I'm looking.
Lose Caffeine over time?
Much of the information that follows I gleaned from detailed discussions with the owners and brew masters of Java Cofee and Tea Co. They have a shop in Houston for 30 years at least and a website. Each coffee is graded by acidity and mild-bold flavor. Between them, my nurse's training which includes chemistry, and experience with coffee over the years, these are some information I have obtained:
From my understanding of the chemistry of caffeine, it does not evaporate. Instead it is the acidty in the coffee that destroys the caffeine over time. Anyone who brews tea knows that tannic acid in the tea destroys the caffine, right? so you try to brew it to reduce the tannic acid production which enhances the caffeine content. Also the flavor and drinkability of the brew for those of us who have sensitive stomachs, as the taste of tannic acid is harsh. The lower acid coffees therefore generally have more caffeine, better taste, If you ask me. I have acid reflux and acidic coffee really upsets my stomach. So I have a built in acid barometer, lol. Coffee that sits on the heat definitely becomes more acidic, harsher tasting and the caffeine might become more concentrated too if the acid were not destroying it. But saving coffee at room temperature does not necessarily lose the caffeine if you have a low acid coffee. I believe Robusto beans also have much higher acidic content than most arabica, giving it less refined taste and destroying some of that extra caffeine. Another source of destroyng the caffene is in the roasting process. What degree heat are the beans at when roasting? My impression of Starbucks Coffee beans are generally roasted fast at higher heat, making them very dark and for my taste, burnt tasting and lacking in caffeine. I work nights and I need decent amounts of caffeine to make it, lol.