Settling the Caffeine Debate - Espresso vs Drip Coffee

Jan. 19, 2010 - PRLog -- Ask almost anyone and they will invariably say that espresso has more caffeine than regular coffee. I mean it makes perfect sense, what else would explain that caffeine buzz we get when we down a shot of Starbucks espresso in the morning?


Interesting, but is this correct? Well that depends on your perspective...

During the 1950's a  typical serving size of a cup of coffee ranged from 4 to 5 oz -  though in the past 50 years or so,  coffee "cup" sizes have nearly tripled  where its now very common to have have your morning cup of Joe served in 6-15oz cups...sometimes even larger.


When comparing drip coffee, the National Coffee Association's estimates a typical 8 oz cup of drip coffee to contain between  65-120 mg of caffeine per cup (per 8 fluid oz).


Why such the large caffeine range?


Well without getting overly technical, several factors such as: brew time, dwell time, water temperature, grind level, roast level, water temperature, bean type, blend, etc. all have a significant affect on final caffeine extraction level.



For example, brews made from pure Robusta will  contain  much more caffeine made from 100% Arabica beans. Compare this to a typical cup of espresso that contains anywhere from 30-50mg of caffeine per 1 fluid oz. and the difference is significant.


So what has more caffeine - espresso or regular?

Well cleary a cup of drip coffee has much more caffeine than espresso - actually about 2-3 times the caffeine (65-120mg) content than espresso (30-50mg). But we cant rest our discussion here, for if you investigate closely, this is not a fair comparison - we need to compare "apples to apples".



To accurately make a comparison between the two, we need to compare concentrations in terms of caffeine per ouce (oz).



In the case of drip coffee,  we divide the 65-120mg of caffeine by its serving size, in this case 8 oz - - resulting in: 8.125 - 15 mg per oz.


Whereas in espresso, even though we start off with about a third less caffeine, all this caffeine is contained in just 1oz of liquid or expressed numerically as 30 - 50mg/oz.


So, we can say that although drip coffee contains much more caffeine than espresso in the beverage form, this is due to its much larger serving size (8oz) than espresso.


But when viewed from a volume perspective (oz) - espresso has a much more  caffeine than drip based on volume (oz). The answer really depends on your perspective...both are correct!!

Espresso
65-200mg of caffeine/8 fl oz
(8.125-15mg/1 fl oz)
   
Drip Coffee
30-50mg/1 fl oz
(30-50mg/ 1 fl oz)


So why do most people believe espresso contains more caffeine than regular drip coffee?

Well, part of the reason this belief has continued to exist is because caffeine itself an intensely bitter compound. Since espresso coffee is roasted much darker than drip coffee - and darker roasts create compounds which are much more bitter - the "connection" between more caffeine and espresso is made. But this is incorrect.


The bitter compounds that arise in darker roasts is not due to more caffeine, but rather bitter compounds created during the Maillard reaction.


It is this much lower concentration of caffeine (per serving) in espresso that allow Italians to drink upwards of 10 to 12 espresso's per day without getting overly jittery - consuming an equivalent amount of  drip would be quite impossible.


Unfortunately its been very difficult to "standardize" the caffeine of various coffee beverages since there are numerous variables need to be controlled including:

   * Beverage Size - is a cup 4oz, 5 oz or 12oz ??
   * Blends - many roaster create their own blends of various beans each with subtle difference in caffeine content.
   * Bean Type - is the blend 100% arabica, robusta or both?
   * Grind - was the coffee prepared with a fine grind, ultra fine grind, coarse, etc?
   * Water Temp - was the coffee prepared with the recommended 195-205F temperature range?
   * Milk - was milk added or now - as this will dilute the caffeine content per ml.
   * Others - machine type, dwell time, etc.



All these factors make the calculation of caffeine in most common beverages a challenge. Hopefully with the implementation of industry standards by organizations such as the SCAA and NCA - we can begin the journey towards creating baselines on caffeine for each of these products.

# # #

Independent technical consulting firm dedicated to coffee testing, quality training and lab equipment sales. We are the leading information portal on all technical matters involving coffee.