Getting the amount of coffee per cup of water right is the single most important step for a great brew. It’s the difference between a weak, sour cup and a balanced, flavorful one that makes your morning.
This guide will give you the exact ratios, explain why they matter, and show you how to adjust them for every brewing method. You’ll learn the simple math that turns good coffee into great coffee.
How Much Coffee Per Cup Of Water
This is the golden question. The standard answer, supported by the Specialty Coffee Association, is a ratio of 1:18. That means 1 gram of coffee for every 18 grams of water. For a standard “cup” in coffee terms (which is 6 ounces, not 8), this works out to about 10 grams of coffee for 180 ml of water.
But “standard” doesn’t mean “only.” This ratio is your starting point, not a rigid rule. Your perfect cup might be a little different.
Why the Coffee-to-Water Ratio is Non-Negotiable
Think of it like baking. Too much flour and not enough water gives you a dry, crumbly mess. Too much water and not enough flour makes a soupy batter. Coffee extraction works the same way.
If you use too little coffee (too much water), the water over-extracts what little coffee is there. It pulls out all the harsh, bitter compounds because it’s working too hard. You get a weak, yet bitter, and hollow-tasting cup.
If you use too much coffee (too little water), the water can’t extract enough of the good flavors. It becomes under-extracted. The result is often sour, salty, and strong in a unpleasant way. It’s a waste of good beans.
The right ratio allows for balanced extraction. The water dissolves the delicious sugars, acids, and aromatic oils just right, leaving the bad stuff behind.
The Tools You Absolutely Need: A Scale
Forget tablespoons and scoops. They are incredibly unreliable. A whole bean and a ground bean take up different volumes. A dark roast is less dense than a light roast. A “scoop” can vary by 5 grams or more.
Using a simple digital kitchen scale that measures in grams is the only way to be consistent. It costs less than a bag of good coffee and will improve your brewing more than any fancy machine. Measure your beans before you grind them for the best accuracy.
Quick Reference: Common Ratios by Brew Method
- Drip Coffee Maker: Start with a 1:17 ratio (e.g., 60g coffee per 1000ml/1L water).
- French Press: Use a stronger 1:15 ratio due to the metal filter (e.g., 55g coffee per 825ml water).
- Pour-Over (V60, Chemex): A middle ground of 1:16 to 1:17 is common (e.g., 22g coffee per 350ml water).
- AeroPress: This is versatile! Ratios from 1:12 (strong) to 1:16 (lighter) work great.
- Espresso: This is a whole different world, using a 1:2 ratio (e.g., 18g coffee yields 36g of liquid espresso).
How to Calculate Your Perfect Ratio
It’s simple math. Decide how much brewed coffee you want in your carafe or cup, then work backwards.
- Choose your target ratio. Let’s use 1:17 as an example.
- Choose your water amount. Let’s say you want 500ml of brewed coffee.
- Divide water by the ratio number. 500ml / 17 = 29.4 grams of coffee.
That’s it! You need 29.5 grams of coffee for 500ml of water. See how easy it is with a scale?
Adjusting for Your Personal Taste
The chart above is a map, but you are the driver. Here’s how to navigate:
- Is your coffee too weak, bitter, or empty-tasting? Increase your coffee dose. Try a stronger ratio like 1:16 or even 1:15. This gives the water more coffee to extract from, leading to a fuller body.
- Is your coffee too strong, sour, or sharp? Decrease your coffee dose. Try a milder ratio like 1:18 or 1:19. This allows for a cleaner, more tea-like extraction.
Always adjust in small increments of 2-3 grams of coffee at a time. Write down what you try so you can remember what worked.
The “Cup” Confusion: Coffee Pot vs. Measuring Cup
This is a huge source of confusion. Your coffee maker’s “cup” setting is not a standard 8-ounce measuring cup. Most machines define a “cup” as 5 to 6 fluid ounces. So a 12-cup brewer is made for about 60-72 ounces of water, not 96.
Always check your machine’s manual. To avoid this entirely, use your scale and the ml markings on your carafe. Measure the water you put in, not the “cups” you select.
Factor #1: Your Roast Profile
Dark roasts are less dense than light roasts because more moisture and mass has been roasted out. If you weigh them, you’ll have more beans for the same weight. They also extract faster because they’re more porous.
You might find you prefer a slightly lower dose of dark roast (a higher ratio, like 1:18) to avoid bitterness. With light roasts, a slightly higher dose (like 1:16) can help bring out their complex acidity and sweetness.
Factor #2: Your Grind Size
Grind size and ratio work together. Finer grinds expose more surface area to water, so they extract faster and more completely. Coarser grinds extract slower.
If you make your grind finer, you might need to slightly reduce your coffee amount or shorten your brew time to prevent over-extraction. If you go coarser, you might need a bit more coffee to get enough flavor out.
Factor #3: The Water Itself
Water is 98% of your cup. If your tap water tastes bad or is very hard, your coffee will too. Use filtered water if possible. Also, water that is too hot (boiling) can scorch coffee; too cold and it won’t extract properly. The ideal range is between 195°F and 205°F (90°C to 96°C).
Step-by-Step: Perfect Drip Pot Coffee
- Weigh your fresh, whole bean coffee. For 1 liter (1000ml) of water, start with 60 grams.
- Grind the beans to a medium consistency, similar to coarse sand.
- Add the ground coffee to a clean paper filter in your machine’s basket.
- Weigh 1000ml of fresh, cold filtered water and pour it into the reservoir.
- Start the brew cycle. If possible, pause it for 30 seconds after the first water hits the grounds to let it “bloom.”
- When brewing is done, give the carafe a gentle swirl and serve immediately.
Step-by-Step: Classic French Press
- Weigh your coffee. For a 34-ounce (1 liter) press, use 55-60 grams. Grind it very coarse, like breadcrumbs.
- Heat 1000ml of water to just off-boil (200°F).
- Add the grounds to the clean, dry press. Pour in about twice as much water as you have coffee to saturate all grounds. Wait 30 seconds for the bloom.
- Pour in the rest of the water. Place the lid on top with the plunger pulled all the way up. Let it steep for 4 minutes.
- Press the plunger down slowly and steadily. Pour all the coffee out into your cups right away to stop the brewing.
Troubleshooting Your Brew
Problem: Coffee is consistently weak and bitter.
Likely Cause: Too much water for the coffee (over-extraction).
Fix: Increase your coffee dose. Use more grams of coffee for the same amount of water (e.g., move from 1:18 to 1:16).
Problem: Coffee is sour and sharp.
Likely Cause: Too little water for the coffee (under-extraction).
Fix: Decrease your coffee dose. Use fewer grams of coffee, or try a slightly finer grind.
Problem: Coffee is flat and muddy (especially in French Press).
Likely Cause: Grind is too fine, or you left it steeping too long.
Fix: Use a coarser grind setting and stick to a 4-minute steep time precisely.
FAQ: Your Coffee Ratio Questions Answered
How many tablespoons of coffee per cup of water?
We strongly recommend using a scale. But if you must, a rough starting point is 1 to 2 tablespoons of ground coffee per 6-ounce cup. This is very imprecise because a tablespoon of a dark roast is lighter than a light roast.
Is the coffee-to-water ratio different for cold brew?
Yes, dramatically. Cold brew uses a much higher coffee concentration because cold water extracts less efficiently. A common ratio is 1:8 (e.g., 100g coffee to 800g water). You then dilute the strong concentrate with water or milk when serving.
How much coffee do I need for 8 cups?
First, define “cup.” If you mean 8 coffee-maker cups (6 oz each = 48 oz total), use about 80-85 grams of coffee at a 1:17 ratio. If you mean 8 measuring cups (8 oz each = 64 oz), you’d need about 113 grams of coffee. This is why a scale and ml are easier!
Does the type of coffee bean change the ratio?
Not drastically, but the roast level does, as mentioned. Origin characteristics (like a bright Ethiopian vs. a earthy Sumatran) are better managed through grind size and water temperature, not usually the core ratio.
My coffee always tastes bad even with the right ratio. What’s wrong?
Check your coffee’s freshness. Beans are best used within 3-5 weeks of their roast date. Stale beans will never taste good. Also, ensure your grinder is clean and your equipment doesn’t have old oils built up.
Building a Habit of Great Coffee
Great coffee is a habit, not a mystery. Start with the standard 1:17 ratio. Use a scale. Use fresh beans and good water. From that solid foundation, you can tweak one variable at a time—ratio, grind, temperature—until you find your personal sweet spot.
The journey to a perfect cup is part of the joy. It makes the ritual of morning coffee even more satisfying when you know you crafted it exactly to your liking. Now you have the knowledge. Your next step is to go and try it.