Brewing Ratios and Temperature

Brewing ratios: know which weight you are measuring

A brewing ratio describes how much dry coffee you use relative to water or finished drink. The distinction matters because filter coffee and espresso normally use different conventions.

For pour-over, cafetière and most immersion recipes, the ratio means dry coffee to input water, both by weight. A 1:16 recipe using 20 g of coffee therefore needs 320 g of water. Input water is everything that enters the brew, including the first small pour used to wet the grounds.

Espresso ratios normally mean dry coffee dose to beverage yield. An 18 g dose producing 36 g of espresso is 1:2. You weigh what lands in the cup, not the water drawn from the machine’s reservoir. Square Mile’s published espresso guide follows this convention, recommending 19 g of coffee for 38 g of espresso.

Do not expect 320 g of filter brewing water to produce 320 g of drink. Some liquid remains with the grounds, while evaporation and equipment retention can also affect the result. Record input water and finished beverage separately if you want to investigate your brewer’s losses.

For the wider relationship between recipes, grind and extraction, begin with grind size and extraction.

The calculation you actually need

For a coffee-to-water ratio of 1:n:

Water required in grams = coffee dose in grams × n

Coffee required in grams = water weight in grams ÷ n

For example, 300 g of water at 1:16 needs 18.75 g of coffee. Alternatively, a practical dose of 60 g per litre gives 30 g for 500 ml of water. Grams per litre is convenient for filling a reservoir; weighing the water is clearer when comparing recipes precisely.

Starting ratios for the main brewing methods

The table separates published recipe examples from broader starting advice. None guarantees a particular flavour: coffee, grind, contact time and brewing technique still matter.

These examples come from SCA brewing guidance, roaster recipes and Bialetti’s operating instructions. In particular, moka pots should not be overfilled or packed differently simply to achieve an internet ratio.

For filter and immersion brewing, 1:15 to 1:17 is a useful experimental band, rather than a verified UK-wide preference. At a fixed water weight, moving towards 1:15 uses more coffee; moving towards 1:17 uses less. The 60 g-per-litre recipes above sit between them, at approximately 1:16.7.

Dilution needs its own record. If you brew a concentrate and add water afterwards, write down the brewing water and added water separately. Water added after removing the grounds changes strength without continuing extraction.

What the SCA Golden Cup guidance actually says

The classic SCAA Golden Cup Standard, revised 23 December 2015, recommends 55 g of coffee per litre of water, plus or minus 10%. Its central dose is approximately 1:18.2; the permitted dosing band is 49.5 to 60.5 g per litre. Therefore, 60 g per litre falls within that recommendation.

The standard also specifies:

• Brew strength: 1.15% to 1.35% total dissolved solids, or TDS.
• Extraction yield: 18% to 22% of the dry coffee’s mass dissolved during brewing.
• Water temperature at contact: 93°C, plus or minus 3°C, meaning 90°C to 96°C.

Strength and extraction are different. Strength describes the concentration of dissolved coffee in the drink; extraction describes how much material has left the grounds. Neither is another name for roast darkness.

Golden Cup guidance is a reference for brewed coffee, not a universal recipe for espresso, moka or cold-brew concentrate. Nor should every SCA document be treated as interchangeable. For example, the separate 2017 home-brewer certification requirements specified reaching 92°C within the first minute and staying between 92°C and 96°C afterwards. That is an equipment test requirement from a particular edition, not an instruction to set every kettle to the same number.

Brewing temperature: what changes, and where to measure it

Hotter water generally speeds extraction, helping soluble material move from the ground coffee into the surrounding water. However, temperature works alongside particle size, time, flow and agitation. A temperature adjustment cannot reliably compensate for every problem elsewhere in the recipe.

There are also several different temperatures in a brew:

• Kettle temperature: the water before pouring.
• Contact or slurry temperature: the water and grounds together.
• Beverage temperature: the coffee collected below the filter.
• Drinking temperature: the coffee when you taste it.

Heat passes into the grounds, brewer and surroundings during preparation. A kettle setting is therefore not a direct measurement of the coffee slurry. Preheating and a consistent pouring routine help make comparisons more meaningful. SCA testing places its temperature sensor within the brewing bed rather than relying on a kettle display.

For an ordinary hot filter brew, 94°C is a reasonable first setting, supported by Origin’s published V60 recipe. Avoid treating a small difference on the display as more important than repeatable weighing and technique.

Adjusting for roast level

As practical trial ranges for kettle water, rather than SCA standards, try:

• Light roast: 94°C to 99°C.
• Medium roast: begin around 94°C, then adjust by taste.
• Dark roast: explore 85°C to 90°C if the usual recipe tastes harsh or excessively roasty.

These ranges are an editorial synthesis, not experimentally established boundaries. Manufacturer recipes support the general direction: Fellow’s published light-roast filter profile uses approximately 99°C, while its dark-roast profile uses approximately 85°C after a hotter bloom. AeroPress recommends substantially cooler starting temperatures, 80°C for dark roasts and 85°C for medium and light roasts, showing why method-specific recipes matter.

The rationale is not simply that light coffee “needs boiling water”. Roasting changes both the material available for extraction and the bean’s structure. Laboratory research has found increasing porosity with darker roasting, providing additional pathways for extraction, although total extraction does not increase indefinitely with roast darkness. Hotter water can help a light roast extract sufficiently within a short recipe; cooler water can help restrain the extraction of an already assertive dark roast.

Do not automatically transfer the light-roast kettle range to an espresso machine. Follow a recipe appropriate to the machine and coffee, keeping dose and beverage yield controlled.

A controlled way to adjust your recipe

Use this short comparison method rather than changing several settings together.

1. Make a baseline. For a V60-style pour-over, use 15 g of coffee and 250 g of water at 94°C, approximately a 1:16.7 ratio.
2. Keep preparation repeatable. Rinse and preheat consistently, discard the rinse water, and use the same grind and pouring sequence. Origin’s example recipe aims for a total brewing time of 3 minutes to 3 minutes 30 seconds.
3. Assess strength first. If the flavour is pleasant but too intense, try adding a measured amount of water to a sample of the finished brew.
4. Test temperature separately. Keep the ratio fixed and compare 94°C with 96°C or 92°C. These are suggested comparison settings, not universal targets.
5. Record dose, water, temperature, time and taste. Repeat the preferred setting before deciding it is better.

A dilution test is especially useful because it separates excessive concentration from an extraction problem. Adding water cannot reverse extraction, but it can reveal whether an otherwise enjoyable brew was simply too strong.

Treat these as diagnostic leads, not proof. Taste symptoms overlap, and bitterness alone does not establish over-extraction. For a fuller diagnosis, read why coffee tastes bitter or sour and grind consistency and taste.

Why strength and extraction deserve more attention than a perfect temperature

A controlled sensory study by Batali and colleagues compared drip coffee brewed at 87°C, 90°C and 93°C. The researchers adjusted brewing conditions to hold strength and extraction at matched targets. Under those conditions, temperature had little effect on the sensory profile compared with strength and extraction.

This does not mean temperature never matters. It means different temperatures can produce similar coffee when other variables compensate. The experiment used one coffee and a particular drip-brewing setup, so it cannot establish a universal optimum for every roast and method.

For practical brewing, choose a repeatable ratio, use an appropriate temperature, then change one thing for a stated reason. Keep the water source consistent too, rather than changing water and temperature together; water hardness, alkalinity and TDS explains that separate set of variables.