Firstly, always ensure your cafetière is thoroughly clean as with use, coffee oils can accumulate on the mesh screen, become stale and can taint the freshly brewed coffee. To ensure the best flavour, after every couple of uses, unscrew the plunger and clean the mesh and screens using hot soapy water, rinsing thoroughly with clean water afterwards.
When brewing, use a standard seven grams per cup measure - roughly one rounded dessertspoon (or two per mug). It's important to never scrimp on the grounds you put in the cafetière - if too few are brewed, then a weak and un-developed cup will result.
If you live in a hard water area, or where the water has a natural taint to its flavour we strongly recommend a jug filter. Water should be freshly boiled just once, as when re-boiled Oxygen is lost which reduces the brightness of the flavours.
NEVER pour boiling water on the grounds, as this will scorch and scald your coffee, and leads to bitterness. Instead, wait for around 20 seconds after the kettle has boiled before pouring.
When ready, pour a small amount of water into the cafetière (no more than a third of the total space). Try to cover all the grounds so they are wetted, and swirl the grounds and water around to mix. Tap down onto a surface and then fill to the top. If the coffee has come from a new, un-opened pack - its freshness will show clearly with a mass of grounds and bubbles forming a frothy cap, so you may need to top up a couple more times, as this settles down.
No matter what size your cafetière is, always leave to steep for 4 minutes before plunging for optimum flavour. Never re-heat the coffee and drink within 20 minutes of brewing; any longer, and the natural oils will contaminate the cup as it cools. This 'stewing' will lead to an unpleasant bitter flavour, which should always be avoided.