Most filter machines are bad, and the differences are specific and checkable.
Brew temperature
The most important specification. Water must reach the coffee at 90 to 96 °C.
Cheap machines brew at 80 to 85 °C, which cannot extract properly. That is why supermarket filter machines make sour, thin coffee regardless of the beans.
Look for certification
The SCA Certified Home Brewer programme and the German ECBC mark test brew temperature, contact time and extraction against a standard.
A certified machine is guaranteed to hit the numbers. It is the fastest way to filter the market.
The shower head
Water should be distributed across the bed, not dropped through a single hole in the middle.
A single-point dispenser wets a small area and lets the rest under-extract. This is the second-biggest failing of cheap machines.
Thermal carafe, not a hotplate
A hotplate cooks the coffee. It is noticeably worse in twenty minutes and unpleasant in an hour.
A vacuum-insulated carafe keeps it drinkable for hours.
Pre-infusion
Better machines pause after wetting the bed to let it degas. It matters most with fresh coffee.
Basket shape
Flat-bottom baskets give a more even bed than cones on a machine, where pour control is not possible.
What does not matter
Programmable timers, LCD displays, built-in grinders on cheap units, “aroma” buttons.
The rule
Temperature and carafe. Everything else is secondary.
Last reviewed 8 August 2026