BartG wrote:I'm considering buying a Bezzera Strega ... One of the things that puzzles me is that baskets of the same size but of different brands produce different results.
It's pretty simple, but goes against the prevailing espresso mythology. If you put 14 grams in a standard Italian double basket, or 7 in a standard Italian single, you wiull get a well extracted shot with a pump machine. Because this is the US and bigger is better here, we use around 18 grams in double baskets and don't use singles at all. This requires a coarser grind and gets us underextracted shots. As long as we were roasting bigger and better too (aka darker), this sort of worked. But now, with the fashion of lighter roasts, the underextracted shots really bite. You would think that we'd just start dosing at 14 grams again, but noooooo, that would be an unamerican and wussy. Instead, we have VST and Strada baskets with "more precise" (aka larger) holes. Hallelujah! now we have a basket that can take 18 grams with as fine a grind as 14 grams in a regular basket, and we can pull properly extracted shots that are bigger and better.
Along comes the Strega, a machine with lots of punch. So much punch, in fact, that if you take an ordinary basket, fill it ith 18 grams, you need to grind as fine as 14 grams in a regular machine. Use a VST basket on a Strega, and you are down to a Turkish grinds. This has the advantage that it's impossible to get a shot that bites; but it has the disadvantage of often producing excessively soft shots.
So my two cents, avoid VST baskets unless you are using really light and fast roasts. Overload the regular baskets with around 18 grams. This will get you shots in the proper extraction range, and you can fine tune it from there.