Equipment
Baskets Are Not Interchangeable
Portafilter baskets differ in capacity, wall shape and perforation pattern, and swapping one for another changes extraction as much as changing the grind does.
A basket looks like a simple metal cup, and it is often treated as a consumable that any equivalent can replace. Its dimensions determine the shape of the puck and how water passes through it.
Capacity sets the dose the basket expects
Baskets are made for a nominal dose, and putting substantially more or less coffee in changes how much headroom sits above the puck.
Too little coffee leaves the puck loose and thin, and water can pool above it before finding a path down, often unevenly.
Too much brings the puck into contact with the shower screen, so it cannot expand when wetted and may crack when pressure releases.
Wall profile changes the puck shape
Some baskets have near-vertical walls producing a cylindrical puck, while others taper, giving a bed that is wider at the top than at the base.
A tapered bed distributes pressure differently through its depth, and the edges behave differently from the centre as a result.
Straight-walled designs are generally regarded as more even, and they have become common on machines aimed at consistency.
Perforation determines where water can leave
The pattern, count and diameter of the holes control how freely the puck can drain and whether it drains uniformly across its base.
Cheaper baskets often have holes that vary in size or are unevenly distributed, so some regions of the puck drain faster than others.
Water follows those preferences, and the resulting uneven extraction looks exactly like a distribution or tamping fault from outside.
Pressurised baskets work on a different principle
Baskets with a single small outlet behind a chamber create back pressure artificially rather than relying on the coffee bed to provide it.
They produce a foamy crema and a drinkable shot from pre-ground coffee, which is why they are supplied with entry-level machines.
They also make grind adjustment largely irrelevant, so anyone trying to dial in on one is adjusting a variable the basket has disconnected.
Changing basket means redialling
Because a new basket alters bed depth, drainage and dose simultaneously, a grind setting carried over from the old one will rarely be close.
Expect to move the grinder noticeably and to reassess the dose, treating the change as a new setup rather than a like-for-like replacement.
The effort is generally worthwhile, since a well-made basket removes a source of inconsistency that no amount of technique can compensate for.
