This graphic illustration from the National Coffee Association provides some amazing statistics in support of the claim that their beverage reigns supreme. I am doing more than my per ‘cupita’ (pun intended) of the nearly half a billion mugs of coffee that Americans drink every day.
Back before we all started working from home during the pandemic and kept on doing so afterwards, my son Hank (now VP of Software Development) and most of our Stat-Ease colleagues jived on java (the real stuff, not the coding language). He and our lead statistician Martin Bezener (now President) conducted a very sophisticated experiment on coffee-grinding, as reported by him in our September 2016 Stat-Teaser. Check out Hank’s dramatic video-detailing of the split-plot coffee experiment.
With the aid of Design-Expert® software’s powerful statistical tools, Martin discovered the secret for making delicious coffee: Use a burr, not a blade, grinder, and go for the finest granulation. Based on these findings, I upgraded my grinder to the highly-rated Baratza Encore, which works really well (though very noisy!).
However, a new study published this May in a Special Issue on Food Physics reveals an uneven extraction in coffee brewing. Evidently, “a complicated interplay between an initial imbalance in the porosities and permeabilities” creates “a cutoff point” where “grinding coffee more finely results in lower extraction.” Along the same lines, but with open content and some nice pictures and graphs to lighten up a lot of dense math (e.g., Navier-Stokes equations for fluid dynamics), see this earlier publication on Systematically Improving Espresso. It “strongly suggests that inhomogeneous flow is operative at fine grind settings, resulting in poor reproducibility and wasted raw material.”
So now that experiments show that finer may not always be better, the quest for the perfect grind continues!