5 Common French Press Mistakes Everyone Makes

This guide covers five settings that shape a French press cup: the grind, the water temperature, the coffee-to-water ratio, the steep time and the stir at one minute. Get those right and the press does what the National Coffee Association (NCA) says it is known for: “Bold flavor and a full body.”

Daily Home Coffee does not run brewing trials. The numbers below come from the NCA’s French press guide and from Wikipedia’s description of how a French press works; each section names its source.

Mistake #1: Using the Wrong Grind Size

A French press needs a coarse grind. The NCA’s grind chart lists French press as “Coarse (like rock salt)”, and Wikipedia describes the right grind as “about the consistency of cooking salt.”

Wikipedia gives three reasons a finer grind causes trouble:

• The plunger gets hard to push: finer grounds have lower permeability, so pressing the plunger takes excessive force.
• Grit gets into the cup: finer grounds are more likely to seep through or around the edge of the filter.
• The coffee turns bitter: finer grounds tend to over-extract.

How to Fix It

Start coarse and adjust by taste. The NCA’s rule of thumb: if the coffee tastes bitter or sour, it may be ground too fine, so go coarser; if it tastes flat or watery, it may be ground too coarse, so go finer.

The NCA recommends a burr grinder, which it says does a better job of creating a consistent grind and extracting flavour evenly. A blade grinder works like a food processor: how long you run it decides the grind size, and it cannot ensure a consistent grind. If you buy pre-ground coffee, note that the NCA’s chart puts drip coffee at a medium grind and French press at coarse, so coffee ground for a drip machine is finer than the press calls for. Ask for a coarse or French press grind instead.

Mistake #2: Getting the Water Temperature Wrong

The NCA gives the brewing temperature for a French press as 93 ± 3°C, which is about 194–205°F. Its method is to bring the water to a boil, remove it from the heat and let it rest for about 30 seconds, then confirm the temperature with a thermometer.

Water heated on the stove or in a microwave is harder to control, the NCA notes, which can affect the quality of the coffee. A thermometer, or a kettle with one built in, takes the guesswork out.

How to Fix It

Boil, take the kettle off the heat, wait about 30 seconds and check the reading. If you want a steadier temperature through the brew, the NCA says double-walled glass and metal presses keep the temperature more consistent during brewing and keep the coffee hot for longer afterwards. The other differences between budget and premium presses are covered in cheap and expensive French presses.

Mistake #3: Ignoring the Coffee-to-Water Ratio

Scooping by eye gives a different cup every morning. The NCA’s ratio for French press is 1 gram of coffee to 10–16 grams of water (1:10 to 1:16). Wikipedia gives a similar starting point: about 30 g of coffee to 500 ml of water, “more or less to taste.”

Using the NCA’s range, the arithmetic for 500 g of water is:

• 1:16 (lighter end): 500 ÷ 16 = about 31 g of coffee
• 1:10 (stronger end): 500 ÷ 10 = 50 g of coffee

Divide your water weight by the ratio number for any other batch size.

How to Fix It

Weigh the coffee and the water. The NCA lists a scale as part of the equipment and says a digital scale helps you brew more consistent coffee and keep track of what worked. Match the press to the batch, too: the NCA notes that you lose quality making a small batch in a larger press.

Mistake #4: Steeping for the Wrong Amount of Time

The NCA gives a brewing time of about 4 minutes of contact between coffee and water, and Wikipedia notes that some writers give around four minutes as the optimal time. The NCA also notes that the longer the brew time, the bolder the cup.

Timing also matters after the steep. The NCA warns that coffee left in a French press “will continue to brew and turn bitter.” Wikipedia says the same: coffee left with the used grounds may become astringent and bitter.

How to Fix It

Start a timer when the water goes in. At about four minutes, press and serve straight away, or pour the rest into another container. Do not leave a second cup sitting on the grounds.

Mistake #5: Skipping the Stir at One Minute

About a minute after the water goes in, the grounds form a crust at the top of the carafe. The NCA calls this normal, and its method includes one more step: stir gently with a wooden spoon to break up the crust. Then put the lid on with the plunger pulled all the way up and steep for about three more minutes.

How to Fix It

The full NCA sequence is short:

1. Boil the water, take it off the heat and rest it for about 30 seconds; check it is around 93 ± 3°C.
2. Add the ground coffee to the carafe, then the hot water.
3. Wait about one minute until a crust forms, then stir gently with a wooden spoon to break it up.
4. Put the lid on with the plunger pulled up and steep for about three more minutes.
5. Gently push the plunger all the way down and serve immediately, or transfer the coffee to another container.

Other Habits That Affect the Cup

• Water choice: the NCA says to use cold water, filtered if possible, and to avoid distilled or softened water.
• Cleaning: the NCA recommends cleaning the whole press after each use, including taking the filter apart and washing it. Coffee grounds and oil left on the device can make the next cup taste bitter.
• Pressing: press gently, as the NCA’s method says. Wikipedia notes that plunging slowly prevents accidental scalding.
• Grinding time: the NCA says grinding whole beans immediately before brewing “guarantees maximum freshness.”

Frequently Asked Questions

Why does my French press coffee taste bitter?

The NCA links bitterness to a grind that is too fine, and warns that coffee left in the press keeps brewing and turns bitter. Try a coarser grind and pour the coffee off the grounds as soon as you press.

Can I use regular pre-ground coffee in a French press?

Yes, though coffee ground for a drip machine is medium on the NCA’s chart, finer than the coarse grind it lists for French press. Wikipedia notes finer grounds are more likely to slip through the filter and over-extract. Look for a coarse or French press grind.

How do I prevent sediment in my French press coffee?

Use a coarser grind: Wikipedia explains that finer grounds are more likely to seep through or around the edge of the filter. The filter itself also matters, which is one of the differences between budget and higher-priced presses.

Should I stir my French press coffee?

Yes, at the one-minute mark. The NCA’s method has you wait about one minute for a crust to form, then stir gently with a wooden spoon to break it up before putting the lid on.

How long can I leave coffee in the French press after brewing?

The NCA says to serve immediately or transfer the coffee to another container, because coffee left in a French press will continue to brew and turn bitter.

Quick Checklist

Coarse grind, like rock salt. Water at about 93 ± 3°C, roughly 30 seconds off the boil. A weighed ratio between 1:10 and 1:16. A gentle stir at one minute, about four minutes in total, then press gently and pour everything off the grounds. If the cup is still not right, change one setting at a time so you can tell which one made the difference.