You're making espresso all wrong!
 

Well - chances are you probably are anyway. This is rather interesting - and the results seem somewhat counter intuitive. There's more in the article that what I pasted here.

https://scitechdaily.com/mathematicians-physicists-and-materials-experts-use-a-shot-of-math-to-brew-a-better-espresso/

Mathematicians, physicists, and materials experts might not spring to mind as the first people to consult about whether you are brewing your coffee right. But a team of such researchers from around the globe — the United States, the United Kingdom, Ireland, Australia, and Switzerland — are challenging common espresso wisdom, finding that fewer coffee beans, ground more coarsely, are the key to a drink that is cheaper to make, more consistent from shot to shot, and just as strong. Their work appears January 22, 2020, in the journal Matter.

“Most people in the coffee industry are using fine-grind settings and lots of coffee beans to get a mix of bitterness and sour acidity that is unpredictable and irreproducible,” says co-senior author Christopher Hendon, a computational chemist at the University of Oregon. “It sounds counterintuitive, but experiments and modeling suggest that efficient, reproducible shots can be accessed by simply using less coffee and grinding it more coarsely.”

Though lots of factors are involved, the norm for brewing an espresso shot is to grind a relatively large amount of coffee beans (~20 grams) almost as finely as possible. The fine grind, common sense goes, means more surface area exposed to the brewing liquid, which ought to boost extraction yield — the fraction of the ground coffee that actually dissolves and ends up in the final drink.

But when the researchers put together a mathematical model to explain the extraction yield based on the factors under a barista’s control — options such as the masses of water and dry coffee, the fineness or coarseness of the grounds, and the water pressure — and compared its predictions to brewing experiments, it became clear that the real relationship was more complicated. Grinding as finely as the industry standard clogged the coffee bed, reducing extraction yield, wasting raw material, and introducing variation in taste by sampling some grounds and missing others entirely.

Hmmm. My alma mater. I do find I use a very large amount of beans for a small amount of espresso.

Coarser grinds leave my shots thin and with lacking crema according to my research- which is done early morning in a brain fog...

so many variables.. but start with a good bean..

This is a couple local engineers and coffee Connoisseurs.

They started a coffee shop using engineering principles to make coffe. Best coffee ever.

https://philsebastian.com/

Just because they can do maths it doesn't mean the clowns can make good coffee. Coffee people make good coffee.

The research also says that you need to run the water faster. I expect the issue is pressure. You need the pressure high to get the crema. And the only way to get pressure with coarse ground coffee is to run the water faster.

they've ignored what is probably the best modern techique-long preinfusion at low pressure followed by normal or profiled extraction. The preinfusion seems to normalize the puck.

Abnormal pucks - it's the kind of first-world problem that keeps me up at night.