The Making of Good Espresso --and Economic Growth

What is a good shot of Espresso? Here is the standard.

The ideal espresso (according to the Instituto Nazionale Espresso Italiano) is a 25ml beverage extracted from around 7g of finely ground coffee, using water at a temperature of 88C, passing through the grains at a pressure of 9 bar. See, dead easy. It should be thick-textured, having emulsified many of the oils, retain most of the volatile aromas and flavours of the bean and be capped with a thick colloidal foam layer - "crema" - reddish, creamy and flecked.

It's taken from a nice writing in The Guardian on 'the God-shot'--the nickname for a perfect home espresso. That article, somehow, reminds me the pursuit of, well, economic growth. We have pretty much had a good idea what espresso economic growth is, and a good deal on the mechanics. At least theoretically.

We know how seductive the crema economic growth is, too, that in Robert Lucas' words in 1988: once one starts to think about them, it is hard to think about anything else.

Yet, when it comes into policy making, the problem is:

Each one of those factors is minutely variable, potentially causing thinness, bitterness, under- or overextraction or - the ultimate humiliation - a thin or patchy crema.