Caffeine content in espresso vs drip coffee. |
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One of the most commonly asked question is how much more caffeine is contained in espresso versus regular drip coffee. Ask almost anyone and they will invariably agree that espresso has more caffeine than regular coffee. Interesting, but are they correct? Well that depends on your perspective. In the US a typically serving size for coffee ranges anywhere from 6-12 oz. According to the National Coffee Association's Coffee Science Source1: A typical 8 oz cup of drip coffee contains 65-120 mg of caffeine per cup (8 oz). Why such the large range? Well without getting overly technical, factors such as brew time, dwell time, water temperature, grind level, roast level, water temperature, bean species, blend, etc. all have a significant affect on final caffeine extraction. For example, brews made from pure robusta will invariable have more caffeine than one made of 100% arabica. Compare this to a typical cup of espresso containing anywhere from 30-50mg of caffeine per oz. and the difference is significant.
So what has more caffeine - espresso or regular? Well cleary a cup of drip coffee has anywhere from 2-4 times more caffeine (65-120mg) than espresso (30-50mg) - but if you look closely, were comparing apples to oranges. To accurately make a comparison between the two, we need to compare concentrations in ternms of caffeine per ouce (oz). In the case of drip coffee, we need to divide the 65-120mg of caffeine by the 8 oz its distributed in - resulting in: 8.125 - 15 mg per oz. Wheras in espresso, even though we start off with about a third less caffeine, its all contained in just 1oz of liquid or 30 - 50mg/oz. So, we can say that although drip coffee contains much more caffeine than espresso, this is due in large to its much larger serving size (8oz) than espresso. But when viewed from a volume perspective (oz) - espresso has a much more caffeine level per volume (oz). So they are both correct.
So why do most people believe espresso has more caffeine than regular? Well, part of the reason is because, in its native form, pure crystalline caffeine is intensely bitter. The compoound is so biter that it is commonly used as the "reference" compound for bitterness detection. Coincidentally, espresso is also very bitter and people tend to associate this for increased caffeine concentration. Makes sense... But actually, the majority of the bitter compounds are not attributed to caffeine but rather to a myriad of byproducts produced during the roasting process, namely the Maillard reactions. It is this much lower concentration of caffeine (per serving) in espresso that allow Italians to drink upwards of 10 to 12 espresso's a day without getting overly jittery - consuming an equvalent amount of drip would be quite impossible. References:
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