Six people asking for coffee can expose the difference between a manufacturer’s “cup” and your favourite mug. Before a gathering, fill one of the cups you will use to a comfortable serving level and measure the water. Multiply by the number of coffee drinkers. Six servings of 150ml mean 900ml of finished coffee; six 250ml mugs mean 1.5 litres. The amount of brewing water will be greater because the grounds retain some of it.
Ask who wants coffee before making the calculation. A guest choosing tea or decaf changes the plan, and a small second batch may be more useful than one oversized pot. Decide whether you want everyone served together or whether a refill will follow. Neither approach is wrong, but guests should not receive half a mug without knowing that another pot is coming.
Use the brewer’s capacity as a limit
Inspect the cafetière’s stated capacity and filling instructions. Leave the space its design requires; do not force an extra serving into the top. A one-litre pot is not a promise of a litre of drink after coffee and brewing have taken their share. If you need more, use two suitable brewers or make separate batches and serve in an order that makes sense.
For a practical starting ratio, 60g coffee to 900g water gives a 1:15 brew. Scale that only within the capacity of your vessel. The National Coffee Association’s French press guide describes measured brewing ratios and a roughly four-minute starting brew. Treat the timing as a recipe to try with your beans, then adjust by taste. A gathering is easier if you have made the recipe once beforehand.
Set out the measured doses before guests arrive, keeping them covered until use. Prepare the cups, spoons and milk where people can reach them without standing beside the kettle. If you have two pots, label the decaf clearly. The distinction should still be obvious after somebody moves a lid or swaps the serving positions.
Make serving part of the recipe
Warm a suitable serving vessel if you plan to transfer the coffee, following its care instructions. Start the timer when water meets the grounds and use the same gentle routine for both pots. When ready, press slowly; do not force a plunger that resists. Keep the vessel on a stable surface and follow the manufacturer’s handling guidance, especially for glass.
Serve promptly or transfer the drink away from the grounds. The NCA recommends immediate serving or transfer rather than leaving brewed coffee in the press. A clean insulated server can be convenient, but check its usable capacity before the party. It should pour comfortably with one hand, close properly and have no old milk or coffee smell in its lid.
If you are serving a first small cup and offering refills, say so. Pour a little into each cup in turn rather than filling the nearest mug to the brim and discovering that the last guest receives very little. Keep the hot pot away from the table edge and leave enough room for people to pass milk without reaching over it.
Choose one manageable variation
A host does not need to offer every café drink. Regular coffee and a small decaf alternative can cover more needs than trying to steam individual milk drinks while dinner plates still occupy the kitchen. If someone wants a weaker cup, offer hot water separately in a suitable vessel. Let people choose their own milk rather than guessing how much each person uses.
Take a note after the gathering: number of drinkers, actual servings and whether you ran short. This is better evidence for the next occasion than the pot’s advertised cup count. If half the second batch remained, reduce the quantity next time; if everyone wanted refills, prepare for two deliberate rounds. Write the successful dose on a card and store it with the pot. At the next gathering, you can put the kettle on without doing the arithmetic again.