# How to Make the Perfect Cup of Coffee

> Five variables decide how coffee tastes: ratio, grind, water, temperature and time. Set them once and every cup after that is repeatable.

Topic: Brewing  
Published: 2026-08-29T09:35:00-04:00  
Updated: 2026-08-29T09:35:00-04:00  
Author: Mical Robert, Editor (https://trysix.online/author/mical-robert)  
Canonical: https://trysix.online/how-to-make-a-perfect-cup-of-coffee

## The short answer

Use 60 g of fresh coffee per litre of water — about 2 level tablespoons per mug — ground to suit your brewer, with water at 195°F to 205°F, for four to five minutes. Those five numbers decide almost everything.

## Key takeaways

- Ratio, grind, water, temperature, time. Fix those five and the cup becomes repeatable.
- 1:16 by weight is the starting point. Move to 1:15 if it tastes thin, 1:17 if it tastes heavy.
- Bitter means over-extracted: coarsen the grind or shorten the time. Sour means under-extracted: do the reverse.
- Roast date matters more than the brand. Coffee more than a month past roasting tastes flat regardless of technique.

Most bad coffee at home is not bad beans or a bad machine. It is one of five numbers being off, and because nobody measures any of them, the same mistake repeats every morning without ever being identified. Set them once and the guesswork stops.

## The five variables

Coffee brewing has exactly two outcomes to control: how much of the ground coffee ends up dissolved in the water, and how much water it is dissolved in. Everything people argue about — kettles, brewers, bloom times — is a way of moving one of those two numbers.

**The five variables, their sensible values, and what happens when you move them.**

| Variable | Start here | If the cup is weak or sour | If the cup is bitter or heavy |
| --- | --- | --- | --- |
| Ratio | 1:16 by weight | Move to 1:15 | Move to 1:17 |
| Grind | Match the brewer | Grind finer | Grind coarser |
| Water | Filtered, not distilled | Check it is not softened | Check it is not heavily mineralised |
| Temperature | 195–205°F | Hotter, within range | Cooler, within range |
| Time | 4–5 min for immersion | Longer | Shorter |

> **Change one thing at a time** — The most common mistake is adjusting grind and ratio together, then not knowing which fixed it. Move one variable, taste, and only then move another.

## Ratio: the one worth weighing

The Specialty Coffee Association's brewing guidance centres on roughly 55 g of coffee per litre of water, and most home brewers land between 55 and 65 g. Call it 60 g per litre, or 1:16 by weight, and you are in the right place for almost any method.

The reason to weigh rather than scoop is density. A tablespoon of coarse-ground light roast weighs noticeably more than the same spoon of oily dark roast, so a scoop recipe drifts every time you change bags. A basic kitchen scale removes that permanently.

**Common serving sizes at 1:16, with scoop equivalents for when there is no scale.**

| Cup | Water | Coffee by weight | Approximate scoops |
| --- | --- | --- | --- |
| Small mug | 240 ml | 15 g | 2 level tablespoons |
| Large mug | 350 ml | 22 g | 3 level tablespoons |
| Two mugs | 700 ml | 44 g | 6 level tablespoons |
| Full carafe | 1 litre | 62 g | About 8 level tablespoons |

## Grind: the one that fixes bad coffee

Grind size controls surface area, which controls how fast water pulls material out of the coffee. Fast methods need fine grinds; slow methods need coarse ones. Getting this wrong is the single most common cause of a bad cup, and the good news is it is also the easiest thing to change.

- Espresso: fine, like table salt. 25–30 seconds of contact.
- Drip and pour-over: medium, like coarse sand. 3–5 minutes.
- French press: coarse, like raw sugar. 4 minutes.
- Cold brew: coarse, and 12–24 hours. See [how to make cold brew coffee](https://trysix.online/how-to-make-cold-brew-coffee).

A burr grinder produces even particles; a blade grinder produces powder and boulders in the same batch, which extract at different rates and give you sour and bitter simultaneously. [How to grind coffee beans](https://trysix.online/how-to-grind-coffee-beans) covers the difference and what to do if you only have a blade grinder.

## Water: 98 percent of the cup

A cup of coffee is about 98.5 percent water, so water that tastes of chlorine makes coffee that tastes of chlorine. A basic filter jug fixes this for a few pounds.

Distilled or heavily softened water is the opposite problem: minerals participate in extraction, and water with almost none of them makes flat, hollow coffee. Ordinary filtered tap water is the right answer for nearly everyone.

**Figure: The five numbers, at a glance**

| Item | Value |
| --- | --- |
| Coffee per litre of water (Grams — a 1:16 ratio) | 60 |
| Water temperature, low end (°F — below this, sour) | 195 |
| Water temperature, high end (°F — above this, harsh) | 205 |
| Contact time (Minutes, for immersion brewing) | 4 |

_Pinned values for a standard immersion or drip brew. Adjust one at a time._

## Temperature: off the boil, not at it

The useful range is 195°F to 205°F. Below it, extraction slows and the cup tastes sour and thin. Above it, you pull more of the bitter compounds and drive off aromatics as steam.

Without a thermometer: boil the kettle, take the lid off, and wait 30 seconds. That lands you in range in an ordinary kitchen. Pouring straight from a rolling boil is the most common temperature error, and it is why coffee made in a hurry so often tastes harsh.

## Time: four minutes, and why not five

For immersion methods — French press, mug steep, anything where the coffee sits in the water — four minutes is the standard. Extraction is fast at first and slows; by four minutes the pleasant soluble material is largely out, and what continues to dissolve is increasingly bitter.

### Diagnosing a cup in three sips

1. **Sour, sharp, empty finish** — Under-extracted. Grind finer, brew hotter within the range, or extend the time. Under-extraction is the more common fault in home brewing, and it is usually mistaken for 'too weak'.
2. **Bitter, drying, lingers unpleasantly** — Over-extracted. Grind coarser, or shorten the contact time. If you brewed in a saucepan, check you did not keep it boiling.
3. **Correct but thin** — Under-concentrated rather than under-extracted. Do not change the grind — change the ratio, to 1:15.
4. **Correct but overwhelming** — Over-concentrated. Ratio again, to 1:17. Resist coarsening the grind; that will make it thin and sour instead.

> **The variable nobody lists** — Freshness outranks technique. Coffee degasses and stales over weeks, and a bag roasted three months ago will taste flat no matter how carefully you brew it. Buy by roast date, not best-before — [where to buy coffee beans](https://trysix.online/where-to-buy-coffee-beans) explains what to look for, and [how to store coffee beans](https://trysix.online/how-to-store-coffee-beans) covers keeping it that way.

## What does not matter as much as you think

- The brewer. A careful mug steep beats a careless machine. If you have no machine at all, [how to make coffee without a coffee maker](https://trysix.online/how-to-make-coffee-without-a-coffee-maker) still gets you to a good cup.
- The gooseneck kettle. It helps with pour-over control and does nothing for immersion brewing.
- The origin, until the basics are right. A superb Ethiopian coffee brewed at the wrong ratio tastes worse than a supermarket blend brewed correctly.
- Roast level, for quality — though it changes the flavour a great deal. See [light vs dark roast](https://trysix.online/light-vs-dark-roast).

## Frequently asked questions

### How much coffee per cup?

About 2 level tablespoons — 15 g — per 240 ml cup, or 22 g per 350 ml mug. By weight that is a 1:16 ratio, roughly 60 g of coffee per litre of water, which is the middle of the range in the Specialty Coffee Association's brewing guidance.

### What temperature should coffee water be?

Between 195°F and 205°F. In practice, boil the kettle and wait 30 seconds. Water straight off a rolling boil is too hot and extracts harshly; water much below 195°F leaves the cup sour and thin.

### Why does my coffee taste bitter?

Almost always over-extraction: the grind is too fine for the method, or the coffee sat in the water too long. Coarsen the grind first, and check you are not brewing above 205°F or leaving a drip machine's pot on its hotplate.

### Does the type of water really matter?

Yes. Coffee is around 98.5 percent water, so chlorinated tap water makes chlorinated coffee. Filtered tap water is ideal. Distilled and heavily softened water are the opposite problem — with almost no minerals, extraction suffers and the cup tastes hollow.

## Sources

- [Coffee Standards](https://sca.coffee/research/coffee-standards) — Specialty Coffee Association. Supports the coffee-to-water ratio range and the brewing temperature window.
- [How to Brew Coffee](https://www.ncausa.org/About-Coffee/How-to-Brew-Coffee) — National Coffee Association USA. Supports the practical brewing guidance on grind size, contact time and water quality.
- [Systematically Improving Espresso: Insights from Mathematical Modeling and Experiment](https://doi.org/10.1016/j.matt.2019.12.019) — Matter (2020) (DOI 10.1016/j.matt.2019.12.019). Supports the relationship between grind size, extraction and reproducibility across brewing.

## Related articles

- https://trysix.online/how-to-make-coffee-without-a-coffee-maker
- https://trysix.online/how-to-grind-coffee-beans
- https://trysix.online/how-to-use-a-drip-coffee-maker
- https://trysix.online/how-to-store-coffee-beans

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