What is a good extraction yield for coffee?

The commonly quoted band is 18 to 22 per cent, and CupTune draws it. Current SCA research shows sensory preference does not map onto one universal correct zone, so treat the band as a place to start comparing rather than a score.

Can I measure extraction without a refractometer?

No. Extraction yield needs a measured dissolved-solids value, and CupTune will not infer one from roast, colour, method or taste. Without TDS you can still compare brews by ratio, time and taste.

Is bitter coffee always over-extracted?

No. Bitterness can come from over-extraction, from a dark roast, from a very high strength or from uneven extraction where some grounds gave up much more than others. That is why the dial-in guide asks for more than one symptom.

Does brewing hotter make coffee stronger?

Not directly. Temperature changes how fast extraction proceeds; strength is set by the ratio. In a controlled study at fixed strength and extraction, brew temperatures between 87 and 93 °C had little sensory effect.

Two numbers, endlessly confused

Strength is not extraction

Strength and extraction are different measurements. Nearly every unhelpful piece of coffee advice comes from treating them as one.

Strength on the vertical axis, extraction yield on the horizontal. The same brew ratio can land anywhere along the horizontal, which is why grind changes taste without changing strength much.

Strength: how concentrated the drink is

Strength is total dissolved solids, TDS, measured as a percentage of the beverage. It answers "how intense is this cup". You raise it by using a shorter ratio and lower it by adding water. A refractometer measures it; nothing about colour, smell or taste measures it, which is why CupTune refuses to estimate TDS and asks you to enter a reading instead.

Extraction yield: how much of the coffee dissolved

Extraction yield is the share of the dry coffee that ended up in the liquid. The formula is visible on our method page and in the calculator: beverage mass × (TDS ÷ 100) ÷ dose × 100. It needs a measured beverage mass and a measured TDS. There is no way to get it from time and grind alone.

Why this distinction pays for itself

A cup can be strong and under-extracted at the same time — lots of coffee, briefly and coarsely brewed. It can be weak and over-extracted — not much coffee, ground fine and left too long. If you only have the word "bitter", you cannot tell those apart, and the fix for one makes the other worse. Separating them is what turns tasting into troubleshooting.

The chart is not a bullseye

The familiar brewing chart has a rectangle in the middle labelled ideal. Current SCA Brewing Chart research shows that sensory attributes do not fit one universal sour-equals-under, bitter-equals-over zone, and that preference varies. CupTune draws the region and deliberately does not draw a target dot inside it.

The temperature result that surprises people

Brewing hotter is widely assumed to extract more and taste different. Batali, Ristenpart and Guinard (2020) in Scientific Reports brewed drip coffee at 87, 90 and 93 °C and, at fixed brew strength and extraction, found brew temperature had no appreciable impact on the sensory profile — the differences tracked TDS and extraction instead. Temperature still matters for how quickly you reach a given extraction. It is a lever, not a flavour dial.

The limits of all of this

TDS meters vary, and home refractometers vary more. Extraction yield is a good comparative measure between your own brews and a poor absolute claim about somebody else's. CupTune will not convert a taste note into a TDS number, and no page here treats a measured number as a verdict about whether you like the coffee.