Let me preface this, my first post in the "Espresso" category, by saying that I'm really not an expert on espresso. Although, some in my family might like to convince you otherwise, I'm just a guy who spent an unusual amount of time obsessing over how to extract the best espresso from his Saeco Espresso Classico machine. That's all.
It's interesting how often the subject of caffeine content comes up in conversation. When I tell people that I typically drink two (sometimes three) espressos in a day, their reaction is usually something like "Oh, I couldn't handle all that caffeine." Whereas, if I said I drank 2-3 cups of coffee a day that would seem normal to most coffee drinkers.
In actuality, it's hard to say how much caffeine an espresso contains because they are pretty inconsistent. When you take into account beans (arabica/robusta/some combination thereof), how finely they're ground, humidity, elevation, temperature, bars of pressure in the machine, and how densely the coffee is packed there is a lot of room for variation. However, this chart puts it somewhere between 30 and 90 mg for a 1 oz. espresso.
When you look at the question ounce per ounce espresso clearly has more caffeine. Regular coffee weighs in at only 13-25 mg per 1 oz., according to the aforementioned chart. But considering a Starbucks Tall coffee is 12 oz. listed as a whopping 260 mg a cup, a regular coffee drinker's daily caffeine intake could be around 780 mg! I probably consume 140 – 210mg a day on my espresso regiment. That's less than 1 average cup of regular coffee a day, and it's spread out over the course of a day.
Since I got rid of my drip coffee maker, and went pretty much espresso-only at home, I've noticed that I've become much more sensitive to caffeine. Now if I have a cup of regular coffee somewhere I really feel it. When I was in college I used to drink 3-4 cups a day easily. Now if I'm feeling wild and decide to have two espressos back to back I get the shakes.
Maybe I'm just getting old.
