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

Let's not play games. I find it counter-intuitive but the dual wall filter basket is the one for beginners. The dual wall filter, with only one, small exit hole in the basket bottom, raises the extraction pressure. Think of it as placing a thumb over the end of a hose. 

 

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.

 

And puck channelling happens less frequently when the dual wall filter baskets are used. 

 

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 variable calls for more skill on the part of the barista.

 

I have heard dual filter baskets called "training wheels" for budding baristas. Uneven tamping or slightly off grind size or weight still results in a espresso consistently acceptable with no fuss, no muss. Sadly, this method also mutes the unique flavour notes found in different coffee beans. But not to worry, most novice espresso makers do not notice.