For people with hard-to-control hypertension, a sudden, big dose of caffeine may boost blood pressure because caffeine constricts blood vessels. But decaf is fine in that respect. And even caffeinated coffee doesn’t increase blood pressure much once you drink it for a week or so, said Van Dam. In fact, the caffeine in coffee seems to have less of an effect on blood pressure than the caffeine in colas because there are so many other substances in coffee that have the opposite effect physiologically from caffeine.

Vietnam produces mostly this type of coffee, and most of it these days comes from Vietnam. Robusta, which is what I both grew and processed in the Congo, is stronger than Arabica, the latter being the whimpier variety. Robusta is what one normally uses to make espresso, 10-20% or so.

Instant coffee, as I understand it, is usually made from Robusta, at least back in the days when i was hanging around on coffee plantations.

If we’re going to be about science, let’s acknowledge that the difference between Robusta and Arabica is the difference between humans and Neanderthals.