I've not been a lover of coffee for some 45 years but was encouraged to try an espresso when a new shop opened, the GCHQ The only coffee I'd ever had was instant during my smoking days.

The espresso was surprisingly palatable, without sugar, and I have a sweet tooth.

Having beans left over from my attempt to make coffee liqueur I ground some beans with a pestle and mortar and, with sugar now, have a strong rich sweet drink. A bit like a cafetière, the grounds are put in a small pot and left to brew for a while. The first pour was good, the second after half an hour and reheated is probably nigh on the best coffee I've ever had.

Looks like I may be on a coffee spree for a while, so invite yourself if you will :)

Caffeine Arabica/Robusta {6/10}mg per bean. 400mg a day is a reasonable max: 66 Aribica beans. However only about 1.5 mg is usual in first extraction. Highly roasted beans will have less caffeine. https://www.caffeineinformer.com/caffeine-content/coffee-beans

. . . weighed out 14.9g in 114 beans before grinding. This is an average of .13g per bean.
https://www.quora.com/What-is-the-average-weight-of-one-coffee-bean-in-grams

So 80 beans could be about 10g and 500mg caffeine