A consistent coffee-to-water ratio is the easiest way to make your morning coffee repeatable. Start with 1 gram of coffee for every 18 grams of water, then adjust for your taste and brewing method.
The quick answer
For automatic drip and most pour-over coffee, use a 1:18 coffee-to-water ratio. That means 20 grams of coffee for 360 grams of water, or about 55 grams of coffee per liter. If you prefer a fuller cup, begin near 1:16 or 1:17.
What does a 1:18 coffee ratio mean?
A brew ratio compares the dry coffee dose with the amount of brewing water. In this guide, the first number is coffee and the second is water. A 1:18 ratio means that every 1 gram of coffee is paired with 18 grams of water.
Weighing both ingredients in grams removes the guesswork caused by scoops, tablespoons, and brewer markings. For normal home-brewing accuracy, 1 milliliter of water can be treated as 1 gram. Place your brewer or water container on a scale, press tare, and pour until you reach the target weight.
Coffee-to-water ratio chart
This chart uses a 1:18 starting ratio. The ounce measurements describe the actual drink size—not the numbered “cups” printed on many coffee makers, which are often only 5 or 6 fluid ounces.
| Water | Coffee at 1:18 | Useful for |
|---|---|---|
| 8 fl oz / 237 g | 13 g | Small mug |
| 10 fl oz / 296 g | 16.5 g | Medium mug |
| 12 fl oz / 355 g | 20 g | Large mug |
| 16 fl oz / 473 g | 26 g | Travel mug |
| 20 fl oz / 591 g | 33 g | Large travel mug |
| 24 fl oz / 710 g | 39.5 g | Two smaller servings |
| 1 liter / 1,000 g | 55.5 g | Small drip batch |
How to calculate any coffee ratio
If you know how much water you want to use
Water weight ÷ ratio = coffee dose. For example, 500 grams of water ÷ 18 = 27.8 grams of coffee. Round that to 28 grams.
If you know how much coffee you have
Coffee dose × ratio = water weight. For example, 30 grams of coffee × 18 = 540 grams of water.
Recommended starting ratios by brewing method
| Brewing method | Starting range | Example |
|---|---|---|
| Automatic drip | 1:17–1:18 | 33–35 g coffee to 600 g water |
| Chemex | 1:16–1:17 | 35–37.5 g coffee to 600 g water |
| Kalita Wave | 1:16–1:17 | 18–19 g coffee to 300 g water |
| French press | 1:15–1:16 | 31–33 g coffee to 500 g water |
| Cold-brew concentrate | 1:5–1:8 | Dilute after brewing to taste |
Espresso and Moka Pot are usually discussed in terms of coffee dose and beverage yield rather than all the water placed in the machine. We will cover those methods separately so the numbers stay useful instead of misleading.
Should you use 1:16, 1:17, or 1:18?
- 1:16 produces a more concentrated cup and is a useful starting point for Chemex or anyone who likes more body.
- 1:17 is a balanced middle ground for pour-over and automatic drip.
- 1:18 creates a slightly lighter, more open cup and aligns closely with the Specialty Coffee Association’s 55-gram-per-liter test recipe for certified home brewers.
Ratio controls concentration, but it does not fix every flavor problem. Grind size, brew time, water temperature, agitation, coffee freshness, and water quality all influence extraction.
How to adjust by taste
| What you taste | Try this first | Why |
|---|---|---|
| Balanced but too light | Use more coffee: move from 1:18 toward 1:17 | Raises concentration |
| Balanced but too intense | Use less coffee: move toward 1:18 | Lowers concentration |
| Weak and sour | Grind finer or extend brew time | Likely under-extraction, not just a ratio problem |
| Dry, bitter, or harsh | Grind coarser or shorten brew time | Likely over-extraction |
What you need
- A digital kitchen scale that reads in grams
- Fresh coffee
- Clean, good-tasting water
- Your brewer and the correct filter
- A note on your phone to record dose, water, grind, time, and taste
The best beginner workflow
- Choose one ratio and keep it constant for several brews. Start at 1:18 for automatic drip or 1:17 for pour-over.
- Weigh the coffee and water instead of using scoops.
- If the cup tastes sour or bitter, adjust the grind before changing several variables at once.
- When the extraction tastes balanced, adjust the ratio slightly to make the cup stronger or lighter.
A ratio is not a commandment. It is a dependable starting point that lets you understand what changed from one brew to the next. Once you can repeat a good cup, experimentation becomes useful instead of random.
Source and further reading
Specialty Coffee Association: Coffee Standards (including SCA-310 Home Coffee Brewers)