French Press Calculator

The commonly recommended range for full-immersion brewing is 1:15 to 1:18. Start at 1:15, which is 30 g of coffee to 450 g of water for a standard 600 mL press. French press tends to brew stronger and bolder than a V60, which uses a paper filter and runs lighter and more delicate. Start at 1:15 and adjust toward 1:18 if you want a lighter cup.

3 to 5 minutes, depending on the coffee and grind. Start the timer when the last of the water hits the grounds. Finer grinds and darker roasts extract faster and need less time; coarser grinds and lighter roasts extract more slowly and benefit from the longer end. Press slowly over about 30 seconds and pour immediately. Leaving coffee on the grounds continues extraction and the cup goes bitter. For large batches, decant straight into a thermal carafe after pressing.

Coarse: think kosher salt or coarse sea salt, not table salt. Too fine and the grounds pass through the metal mesh during pressing; the cup turns muddy and bitter. A burr grinder on its coarser end settings will get you there. Blade grinders produce enough fines to grit the cup regardless of setting.

French press is immersion brewing, so water temperature shapes the cup more than a single target number suggests. Match the temperature to the coffee and expect some trial and error. As a starting point: lighter roasts prefer hotter water, around 95 to 96 °C (203 to 205 °F). Darker roasts tend to do better slightly cooler, around 90 to 93 °C (194 to 199 °F). Adjust based on what you taste.

Three likely causes: grind too fine (fines over-extract and slip through the mesh), steep time too long (coffee left on grounds after pressing), or ratio too strong for the coffee you're using. Check grind first; it's the most common culprit. If the grind is right and the steep time is correct, try loosening the ratio by one notch (1:15 to 1:16).

French press is a viable vessel for a small-batch room-temperature steep, but the ratios are different. Ready-to-drink cold brew runs around 1:15 with a 12 to 18-hour steep; cold-brew concentrate runs 1:5 to 1:8 and needs dilution before drinking. Use the cold brew calculator for those recipes.

Keep the ratio constant and multiply both numbers. A 30 g / 450 g recipe for a 600 mL press scales to 40 g / 600 g for an 800 mL press. Enter the new dose or water amount in the calculator above and the ratio stays fixed while the absolute amounts adjust.