Coffee Brew Ratio, From Espresso to Cold Brew
A brew ratio is written as coffee to water, both by weight: 1:16 means one gram of ground coffee for every sixteen grams of water. Grind 20 g and you need 320 g of water. Work backwards and a 500 g mug of filter coffee at 1:16 needs 31 g of coffee. The calculator above moves between the three numbers you actually have on the counter — dose, water and brewed yield — so two of them are enough to find the third.
Ratios run from about 1:1.5 for a ristretto to 1:17 for a clean filter brew, and that spread follows from contact time and pressure rather than taste. Espresso forces a little water through a fine bed in under thirty seconds, so it needs concentration to extract anything. A French press leaves coarse grounds steeping for four minutes, where the same ratio would give a muddy cup.
Why the Ratio Is by Weight and Not by Scoop
Volume dosing cannot repeat, because coffee is not a consistent material. A tablespoon of fine espresso grind packs more mass into the same spoonful than a tablespoon of coarse grind, since smaller particles leave fewer gaps between them. A tablespoon of dark roast weighs less than a tablespoon of light roast, because roasting drives off moisture and leaves the bean more porous. Change the grind and the roast and the same level scoop holds anywhere from roughly 4 g to 8 g.
A scale that reads to 0.1 g removes the problem. On espresso it is not a luxury: half a gram of dose shifts the yield and the flavour, and dialling in a new bag is mostly a matter of moving the dose in small steps. Filter is more forgiving, but the same scale also weighs your water, which is the only reliable way to hit a ratio — a measuring jug is no better than a scoop, because water by volume and water by weight agree at only one temperature.
The Ratios, Method by Method
Treat the ranges below as the working span for each method rather than a rule you break by sitting at the edge of it. A 1:15 pour-over and a 1:16 pour-over are both correct, one stronger than the other. Grind and water temperature are not optional, because those two decide whether the water extracts the coffee properly in the first place.
| Method | Ratio | Grind | Water Temp | Notes |
|---|---|---|---|---|
| Espresso, ristretto | 1:1.5 | Fine | 92–94 °C | An 18 g dose gives a 27 g yield |
| Espresso, standard | 1:2 | Fine | 92–94 °C | 18 g gives 36 g in 25–30 s at 9 bar |
| Espresso, lungo | 1:3 | Fine | 92–94 °C | 18 g gives 54 g; thinner and bitter beyond |
| Moka pot | about 1:10 | Fine-medium | Hob heat | Fill the basket level; stop it as it starts to sputter |
| AeroPress | 1:12–1:15 | Medium-fine | 80–90 °C | Short steep, then press steadily rather than hard |
| Pour-over (V60, Chemex) | 1:15–1:17 | Medium | 92–96 °C | 2½–3½ minutes total, bloom included |
| Drip filter machine | 1:16–1:17 | Medium | 92–96 °C | The machine sets the cycle; you control dose and grind |
| French press | 1:14–1:16 | Coarse | 92–96 °C | 4 minute steep, then press and decant immediately |
| Cold brew concentrate | 1:8 | Coarse | Room temp or fridge | Steep 12–18 hours, then dilute about 1:1 |
| Cold brew, ready to drink | about 1:15 | Coarse | Room temp or fridge | This is the concentrate already diluted |
| Siphon | 1:15 | Medium | Near boiling | Vacuum pot; very clean cup, short contact time |
Espresso is the one method where the ratio is written against the yield rather than the water, because you cannot weigh the water that the pump pushes against the coffee bed. An 18 g dose producing 36 g is a 1:2; the same dose producing 27 g is a ristretto. Cold brew sits at the other extreme: 1:8 makes a concentrate steeped 12 to 18 hours, which you dilute about 1:1 with water or milk before drinking.
Extraction Yield, TDS and How to Read a Bad Cup
Two measurements sit underneath every good cup. Extraction yield is the percentage of the dry coffee's mass that dissolved into the water; total dissolved solids, or TDS, is the concentration of those solids in the finished liquid. Yield is how much you took, TDS is how strong it tastes, which is why a brew can taste weak and be over-extracted at the same time. The Specialty Coffee Association's guideline band for filter coffee is roughly 18–22% extraction yield and 1.15–1.35% TDS, measured with a refractometer.
That band is a guideline rather than a law, and refractometers carry real measurement error, particularly on a double espresso. Its genuine use is diagnosis: thin and sour with a low reading means under-extraction, dry and bitter with a high one means over-extraction.
| What You Taste | What It Means | First Change |
|---|---|---|
| Sour, salty, thin, abrupt finish | Under-extracted | Grind finer |
| Bitter, dry, hollow, lingering | Over-extracted | Grind coarser |
| Clean but faint, no sourness | Right extraction, too little coffee | Tighten the ratio |
| Sour and bitter in one cup | Uneven extraction, not a ratio fault | Fix distribution and pour |
| Strong but flat and papery | The water is at fault, not the dose | Change the water |
The fix order is grind first, ratio second, temperature third. Grind is the largest single lever you have: a small move on the dial changes the surface area available to the water and shifts extraction yield more than any other adjustment on ordinary equipment. The ratio mostly changes strength, because adding water dilutes the cup without pulling much more out of the grounds. Temperature comes last because it is the hardest thing to change. And change one variable at a time — grind finer and raise the temperature in the same brew and you learn nothing you can use again.
Grind, Roast Level and Water Temperature
Roast level decides how readily the coffee gives up its flavour. A light roast has been taken less far through the roaster, so it keeps more moisture and its cell structure is denser and less fractured. Dense coffee is harder for water to penetrate, which is why a light filter roast wants water at the top of the 92–96 °C range and often a slightly finer grind than the same coffee roasted darker. A dark roast has been puffed up and made porous by the roasting, so it extracts quickly and turns ashy at the top of the range. When a dark roast tastes thin and burnt at settings that flattered a light one, the answer is a coarser grind and cooler water, not more coffee.
Those ranges are working figures rather than guesses: 92–94 °C for espresso, 92–96 °C for filter methods, and 80–90 °C for an AeroPress, where the fine grind and short contact time would over-extract at the top of the filter range. Without a thermometer, water straight off the boil is roughly 98–100 °C at sea level and falls quickly in an open kettle; a thirty-second wait lands in the filter band. At altitude water boils cooler, so a recipe that works at sea level can taste sour higher up.
Freshness, Degassing and the Date on the Bag
Coffee releases carbon dioxide for days after roasting, and that matters in the brewer because gas pushes water away. Brew a coffee two days off the roast and the bed bubbles violently, the water runs unevenly through it, and the cup tastes sharp however careful your technique. Wait too long instead and the aromatics oxidise, and the coffee tastes of cardboard. For filter, roughly 4 to 14 days off the roast is the practical window.
The date on the bag is the most useful single piece of information you have. Supermarket coffee usually carries a best-before rather than a roast date, and a best-before is typically set about a year after packing, so a bag with ten months left on it could have been roasted last week or last summer. A printed roast date makes a coffee a genuinely different product rather than a marketing upgrade. Store beans sealed, cool, dark and dry, whole if you can — the hopper of a grinder beside a warm machine is one of the worst places in the kitchen for them.
Water: The Ingredient Nobody Weighs
Coffee is roughly 98% water, so the water is not a neutral carrier. What matters most is total hardness — dissolved calcium and magnesium — together with alkalinity, which buffers the coffee's acidity. The usual target is around 75–125 ppm total hardness. Distilled and reverse-osmosis water sit close to zero and extract poorly, giving a flat, papery, sometimes hollow cup, because it is the minerals that help carry flavour compounds out of the grounds into solution. Water far above the target tastes dull and heavy and scales the kettle and the boiler.
| Water | Rough Hardness | What It Does in the Cup |
|---|---|---|
| Distilled or reverse osmosis | Close to zero | Extracts poorly; flat, papery, hollow |
| Soft | Under about 75 ppm | Workable; can taste thin and under-built |
| Target band | 75–125 ppm | Enough minerals to extract fully, not enough to flatten |
| Hard | Well above 125 ppm | Dull and flat, and it scales the boiler and kettle |
The bands above are practical guidance rather than a single official threshold, and the Specialty Coffee Association publishes a fuller specification covering alkalinity as well as hardness. For most kitchens the test is simpler: if the tap water tastes clean and the kettle stays free of heavy scale, brew with it. If it reeks of chlorine, or limescale builds up within weeks, use a carbon filter jug.
Frequently Asked Questions
Start at 1:16, with 1:15 to 1:17 as the working range. For a 300 g brew that is 19 g of coffee and 304 g of water. Use a medium grind and water at 92–96 °C, and aim for the whole brew to finish in 2½ to 3½ minutes including the bloom. A drawdown much faster than that means the grind is too coarse; a stalled, pooling bed means it is too fine.
Sour, salty and thin together nearly always means under-extraction: the water left the coffee before it took the sweetness out. Grind one step finer first. If that does not help, check the water temperature, because water below the range for your method will not extract properly whatever you do to the grind. Very light roasts can taste sharp even when brewed correctly, so try the finer grind before blaming the beans.
Bitterness, dryness and a hollow aftertaste point to over-extraction, so grind coarser first. In a French press bitterness is more often a steeping fault than a grind fault: the grounds left in the pot keep extracting after you press, so press and pour the whole pot at once. In espresso, a shot running well past 30 seconds is the usual cause.
For espresso, yes — half a gram changes the yield and the taste of a double. For filter, 1 g resolution would do, but a 0.1 g scale costs little, weighs the water as you pour, and covers both. The alternative, a scoop, varies by several grams with grind and roast level and cannot be corrected for.
For filter, roughly 4 to 14 days off the roast. Earlier than that the coffee is still releasing carbon dioxide heavily, which makes the brew uneven and sharp; after about two weeks the aromatics have faded and the cup tastes flat. These are working limits, not hard boundaries, and espresso often prefers a slightly longer rest. A bag with no roast date leaves you no way to tell where in that window your coffee sits.
1:8 for a concentrate, using a coarse grind and a 12 to 18 hour steep at room temperature or in the fridge, then strained. Dilute it about 1:1 with water or milk before drinking, which brings it close to 1:15. Cold brew sold ready to drink has already been diluted. Fridge steeping is slower and extracts less of the bright acidity, so pick your method and keep it constant.
Usually yes, if it tastes clean on its own and your kettle does not fur up quickly. Aim for roughly 75–125 ppm total hardness with low enough alkalinity that the water does not buffer away the coffee's acidity. If it smells of chlorine, run it through a carbon filter jug. Do not use distilled or reverse-osmosis water alone: with almost no dissolved minerals it extracts poorly.