Breville Barista Touch Espresso machine: Should a novice use the dual-wall or the single-wall filter basket?

Let me get right to the point: I find it counter-intuitive that the dual-wall filter basket is the basket for beginners. I expected to see holes, lots of holes, in the filter basket bottom. It just seemed reasonable.

 

The dual-wall filter basket, the one with only one, small, exit hole in the bottom, looks strange. What advantage could there possibly be? Answer: the one hole raises the extraction pressure. Think of it as placing a thumb over the end of a hose. And why is this good?

 

The high pressure created by forcing the espresso through one, final, small hole smooths over flavour imperfections while producing a thick and stable crema. Critics see this as a cheat: ample crema created without perfect extraction.

 

Puck channelling happens less frequently when the dual-wall filter basket is used. Grind size, dose weight and tamping consistency all have less influence on the resulting brew. On the down side, pucks are often somewhat wet when the dual-wall filter basket is used. Many folk just ignore the wet puck if the espresso is good. 

 

On the other hand, the single-walled filter basket, with rows and rows of small perforations in the stainless steel bottom, depends on proper grind size, dose weight and consistent tamping to control extraction pressure. Controlling the variables calls for more skill on the part of the barista.

 

I have heard dual-walled filter baskets called "training wheels" for budding baristas. Despite uneven tamping, incorrect grind size or dose weight errors one still pulls consistently acceptable espresso shots with no fuss, no muss. Note the word acceptable. Sadly, the dual-walled filter basket also mutes the unique flavour notes found in different coffee beans. But, not to worry, most novice espresso makers do not notice. Acceptable is acceptable.