Espresso is weaker than drip. It’s an “urban myth” that espresso is stronger.
In espresso, there is less time where water is contacting the grounds, doing the caffeine extraction than drip. (that’s the espress/express part).
Beans are often washed prior roasting so that must be where this coffee maker preserves caffeine.
But I bet this still tastes like burnt rubber - ala Starbutts.
Not according to my research: According to the Mayo Clinic, an 8 oz expresso has between 320 mg and 600 mg of caffeine vs. 95 mg to 200 mg of caffeine for 80z brewed coffee. (http://www.mayoclinic.com/health/caffeine/AN01211)
According to Wiki, one liter of expresso has between 1,691–2,254 mg of caffeine vs. 555–845 mg of caffeine for a liter of drip coffee. (http://en.wikipedia.org/wiki/Caffeine)
It's not even close -- Espresso has more caffeine per volume than drip coffee by a long shot.