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Why is my filter machine coffee weak?

Almost always the ratio. Machine markings assume far less coffee than 60 g per litre.

Weak machine coffee is usually not the machine’s fault.

The ratio

60 g of coffee per litre of water. That is roughly a heaped scoop and a half per cup, and it is far more than machine markings suggest.

Most manufacturers assume one level scoop — around 7 g — per 150 ml cup, which is about 46 g per litre. Noticeably weak.

Weigh the coffee. Most complaints about machine coffee end here.

Bed depth

A machine basket wants to be at least half full. Brewing two cups in a ten-cup basket gives a shallow bed the water channels through.

If you routinely brew small amounts, a smaller machine is the fix.

Grind

Medium, and adjust by drain time. Under 4 minutes for a full batch is too coarse.

Pre-ground supermarket filter coffee is about right in size and stale, which is a different problem.

Temperature

If the machine brews below 90 °C, the coffee will be weak and sour and nothing you do about ratio will fix it.

Test it: brew into a jug and measure the temperature of the output immediately. It should be over 80 °C in the carafe, which implies a higher brew temperature at the bed.

The single-point dispenser

If water drops through one hole, part of the bed is barely wetted. Some people stir the bed once, mid-brew — it is inelegant and it works.

The order

Weigh the coffee. Fill the basket properly. Then question the machine.

Last reviewed 8 August 2026