Brew
Grinding, water and extraction: turning roasted coffee into a drink.
Fundamentals
What every brew method shares- FundamentalWhat extraction isHow water takes coffee out of the grounds – what dissolves and what is only carried along, how broken and intact cells give up their contents, and why the brew changes as extraction goes on.Source-checked
- FundamentalExtraction yield and TDSHow strong a coffee is (total dissolved solids) and how much of the grounds ended up in it (extraction yield) – the two numbers behind the brewing control chart, how to measure them and what they say about flavour.Source-checked
- FundamentalExtraction variablesThe settings a brewer controls – grind, contact time, flow, temperature, ratio, pressure, the coffee and the water – what each does to extraction yield and strength, and how they interact.Source-checked
- FundamentalCO₂ and the bloomWhat happens to the carbon dioxide left in ground coffee when hot water reaches it – the bloom in filter brewing and the crema on espresso – how much gas remains at brewing time, and what is known about its effect on extraction.Source-checked
- FundamentalBrew temperatureHow hot the water is when it meets the coffee – the ranges that standards specify, what heat does to the speed and end point of extraction, where heat is lost, and why water boils below 100 °C at altitude.Source-checked
- FundamentalBrew ratio and strengthHow much coffee is used for how much water, how that ratio is written, and how it sets the strength of the cup – with the published specifications and what sensory studies say about strength and liking.Source-checked
- FundamentalBrewing control chartThe chart that plots brew strength against extraction yield, with brew ratios as diagonal lines and target boxes for filter coffee – where it came from, which targets exist and what sensory research since 2020 has found.Source-checked
Water
5 entries- WaterWater for coffeeWhy brewing water matters, where its minerals come from, how hardness and alkalinity shape flavour and machines, which targets are published, and how water is measured and treated.Source-checked
- WaterHardness and alkalinityWhat total, carbonate and non-carbonate hardness and alkalinity mean, how the carbonate system ties them to pH, how alkalinity buffers coffee acids, and how both values are measured and reported.Source-checked
- WaterWater minerals and flavourWhat studies have measured about how the minerals in brewing water change coffee – alkalinity lowers perceived acidity, while the effects of hardness, magnesium and sodium are smaller or unsettled.Source-checked
- WaterMeasuring waterHow to find out what is in your brewing water – drop tests for hardness and alkalinity, conductivity meters, chlorine tests, water reports and bottle labels – and what each method can and cannot tell you.Source-checked
- WaterWater treatmentHow filters, ion exchangers, reverse osmosis and added salts change brewing water – what each removes or adds, which suits which tap water, and how to keep a treatment system clean and working.Source-checked
Grinding
6 entries- GrindingGrindingWhy roasted coffee is ground before brewing – it breaks open cells and shortens the paths that solubles must travel – and what grind size, freshness, heat, moisture and static change in the cup.Source-checked
- GrindingGrinder types and burrsHow coffee grinders break beans – blades, conical burrs, flat burrs and industrial roller mills – and how the shape, gap, wear and temperature of the grinding parts change particle sizes, fines, heat and retention.Source-checked
- GrindingParticle size and finesGround coffee is a mix of sizes, usually with two peaks – small cell fragments called fines and much larger particles. This spread shapes how fast coffee extracts and how easily water flows through the bed.Source-checked
- GrindingWhat affects grindingThe same grinder setting does not always give the same grind. Roast degree, water in the bean, bean temperature and the grinder itself shift the particle sizes; several commonly named factors have not been measured.Source-checked
- GrindingStatic and retentionGrinding charges coffee particles with static electricity, so grounds clump and cling inside the grinder. What sets the charge, what a little water on the beans does, and how much coffee stays behind between doses.Source-checked
- GrindingGrinder careWhat builds up and wears inside a coffee grinder – old grounds, oxidising coffee oil, fines, worn or misaligned burrs, microbes – and what food-hygiene rules and the few studies say about cleaning it.Source-checked
Brew methods
5 entries- Brew methodPour-over and immersionHow the main non-espresso brew methods work – percolation, where fresh water flows through the grounds, and immersion, where all the water steeps with all the coffee – and what each device changes.Source-checked
- Brew methodPour-over techniqueHow a manual pour-over works step by step – ratio, grind, water temperature, bloom, pouring and drawdown – how filter and dripper shape change the cup, and how to adjust the grind, with published example values.Source-checked
- Brew methodCold brewCoffee extracted with water at room temperature or colder over hours instead of minutes – how immersion and slow-drip methods work, what low temperature changes in the cup, and how cold brew is kept safe.Source-checked
- Brew methodMoka potA stove-top coffee maker in which heated air and vapour in a closed lower chamber push water up through a bed of ground coffee into an upper chamber, at far lower pressure than an espresso machine.Source-checked
- Brew methodFilter coffee machinesAn automatic drip machine heats water in a tube, lifts it with steam bubbles and sprays it over ground coffee in a paper filter. The entry covers its parts, its test standards and the rules on holding and switch-off.Source-checked
Espresso
7 entries- EspressoEspressoA small, concentrated coffee made by forcing hot water at high pressure through a compacted bed of ground coffee. It carries dissolved solids, oil droplets, fine particles and a foam, the crema.Source-checked
- EspressoHow an espresso machine worksAn espresso machine heats water, pressurises it to about 9 bar, spreads it over a compacted bed of fine coffee and ends the shot. The entry covers how pumps, boilers, groups and levers do these jobs and how the coffee bed resists the water.Source-checked
- EspressoEspresso recipes and ratiosHow an espresso recipe is written – dose, beverage mass, ratio, time, temperature and pressure – what each setting does to strength, extraction and flavour, and how baristas calculate and adjust a shot.Source-checked
- EspressoPuck preparationHow ground coffee is dosed, distributed and tamped into an espresso basket. The aim is an even bed, so that water passes through all of it instead of channelling through a few paths.Source-checked
- EspressoReading a shotWhat can be seen and measured during and after an espresso shot – flow, time, beverage weight, colour, crema, the spent puck and strength – and how much each one tells about the extraction and the cup.Source-checked
- EspressoHistory of the espresso machineHow the espresso machine developed from steam-boiler bar machines to spring levers, hydraulic groups and pumps with heat exchangers, dated from patent records and historians, with the disputed firsts marked.Source-checked
- EspressoEspresso machine careWhat builds up inside an espresso machine – scale, milk residues and bacteria – what tests found about metals released after descaling, and what the evidence does and does not say about cleaning.Source-checked
Milk
1 entrySingle-serve
4 entries- Single-serveCoffee capsulesA coffee capsule is a sealed single dose of ground coffee that its machine pierces and brews under pressure. How a capsule opens and brews, what studies measured in the cup, and where the system came from.Source-checked
- Single-serveHow capsules are madeHow single-serve coffee capsules are made – forming the body, grinding and degassing the coffee, dosing, removing oxygen and sealing the lid – and what storage studies show about barrier, oxygen and freshness.Source-checked
- Single-serveCapsules and the environmentWhat life-cycle studies show about the environmental cost of a capsule coffee compared with other brewing methods, what happens to used capsules, and what the EU packaging rules require of capsules and pads.Source-checked
- Single-serveSingle-serve beyond capsulesThe other ways to brew one cup from a pre-measured dose – paper espresso pods, soft pads for pad machines, drip bags hung on the cup and coffee bags steeped like tea – how each is built and what the few studies measured.Source-checked
History
2 entries- HistoryHistory of brewingHow coffee brewing moved from boiling in a pot to drip pots, percolators, vacuum brewers, paper filters and plunger pots, and which of the usual dates rest on patents and which only on later accounts.Source-checked
- HistoryOttoman coffee and the cezveHow Turkish coffee is made in a cezve – fine coffee, water and often sugar heated together until it foams and served with its grounds – what has been measured in the cup, and what the heritage listings say.Source-checked