Coffee Extraction Calculator: TDS & Extraction Yield
Work out your coffee extraction yield from a refractometer TDS reading, for pour over, French press or espresso. See your brew on the brewing control chart, including the new 2023 SCA chart, and what to change.
The maths and targets follow the SCA brewing control chart and peer-reviewed UC Davis research, listed in the sources. How we test · Editorial policy
Extraction targets at a glance
| Brew | Strength (TDS) | Extraction | Typical ratio |
|---|---|---|---|
| Pour over & drip | 1.15–1.35% | 18–22% | 1:15–1:17 |
| French press & immersion | 1.15–1.35% | 18–22% | 1:15–1:17 |
| Espresso | 8–12% | 18–22% | 1:2 |
Filter targets: the SCA's classic Golden Cup ranges. Espresso: the usual working range. Ratios are grams of water (or espresso out) per gram of coffee.
Extraction yield is the share of your ground coffee that ends up dissolved in the cup. To work it out, multiply the weight of the brewed coffee by its TDS (total dissolved solids, the strength a refractometer reads) and divide by the weight of the coffee you used. For example, 220 g of pour over at 1.35% TDS from 15 g of coffee is a 19.8% extraction. The extraction calculator at the top of this page does this for pour over, immersion and espresso. It places your brew on the brewing control chart and tells you what to change.
- TDS is strength: how much coffee is dissolved in the drink. Filter coffee is usually 1.15–1.35%, espresso about 8–12%.
- Extraction yield is how much you took from the beans: 18–22% is the classic target for both.
- The formula: extraction yield = brewed coffee (g) × TDS (%) ÷ coffee (g).
- Strength comes mostly from the ratio; extraction comes from grind, time, temperature and agitation.
- The 2023 brewing control chart shows there’s no single ideal. Different drinkers prefer different corners of the chart.
- Taste first. TDS numbers help you repeat a cup you love and fix one you don’t.
What TDS and extraction yield mean
Two numbers describe a brewed coffee. They’re easy to mix up, because both get called “strong”.
- TDS (total dissolved solids) is the strength of the drink: the percentage of the liquid that is dissolved coffee. A filter coffee at 1.30% TDS is 98.7% water. You feel TDS as body and intensity: thin and watery when it’s low, heavy and intense when it’s high.
- Extraction yield (EY), also called percent extraction, is how much of the coffee grounds you dissolved, as a percentage of the dry coffee. Roughly 30% of a roasted bean can dissolve at all. Most brews take 18–22%. Extraction shapes flavour more than strength: too little tastes sour and hollow, too much tastes bitter and dry.
They move independently. A cup can be weak but over-extracted (a lot of water through finely ground coffee), or strong but under-extracted (a short ratio with a coarse grind). That’s why taste alone can mislead you, and why the numbers help.
How to calculate extraction yield
You need three numbers: the dry coffee weight, the weight of the brewed coffee and its TDS. Brewed coffee × TDS gives the grams of coffee dissolved in the cup. Divide that by the dose and you have the share of the coffee you extracted.
Extraction yield (%) = brewed coffee (g) × TDS (%) ÷ coffee (g)
| Example | Coffee | Brewed coffee | TDS | Extraction yield |
|---|---|---|---|---|
| V60 pour over | 15 g | 220 g | 1.35% | 220 × 1.35 ÷ 15 = 19.8% |
| Batch drip | 60 g | 880 g | 1.25% | 880 × 1.25 ÷ 60 = 18.3% |
| Espresso | 18 g | 36 g | 9.5% | 36 × 9.5 ÷ 18 = 19.0% |
| Ristretto | 18 g | 27 g | 12.0% | 27 × 12 ÷ 18 = 18.0% |
If you weighed the water instead
Spent coffee grounds hold on to about 2.1 g of liquid per gram of coffee (Ristenpart and Kuhl, UC Davis Coffee Center). In a pour over, that liquid never reaches the cup, so subtract it. In a French press or other full immersion, the liquid in the grounds is just as strong as your cup, so it still counts as extracted. The calculator handles both cases:
- Pour over and drip, water weighed: EY = TDS ÷ (1 − TDS) × (water − 2.1 × coffee) ÷ coffee
- French press and full immersion: EY = TDS ÷ (1 − TDS) × water ÷ coffee
Here TDS is written as a fraction (1.30% = 0.013). The “÷ (1 − TDS)” part accounts for the dissolved coffee adding to the weight of the liquid. These are the formulas behind the 2023 brewing control chart. For a 250 g French press made with 15 g of coffee and reading 1.25% TDS, the extraction is 1.25 ÷ 98.75 × 250 ÷ 15 = 21.1%.
The coffee brewing control chart
The brewing control chart puts the two numbers on one graph: extraction yield along the bottom, TDS up the side. It was published by Ernest Lockhart of the Coffee Brewing Institute in 1957 and is still taught in barista courses today. Its centre box, 1.15–1.35% TDS at 18–22% extraction, is the basis of the Specialty Coffee Association’s Golden Cup standard for filter coffee.
The diagonal lines on the chart are brew ratios. For any ratio, as you extract more, strength rises along that line. This tells you which control does what:
- To move up or down (strength), change the ratio. More coffee for the same water makes a stronger cup. Our coffee ratio calculator helps.
- To move left or right (extraction), change how you brew. Grind finer, brew longer, use hotter water or stir more to extract more. Do the reverse to extract less. Grind is the biggest lever. See the grind size chart.
The new brewing control chart (2023)
The classic chart says where coffee is “ideal”, but not why, or for whom. Researchers at the UC Davis Coffee Center, funded by the Specialty Coffee Association, brewed drip coffees across the chart: TDS from 1.0% to 1.5% and extraction from 16% to 24%. Trained tasters profiled them and black-coffee drinkers rated them. The results were published in 2023 as a new brewing control chart, and they change how to read the old one.
- Strong and under-extracted (top left) tasted of acidity, sourness, citrus and red fruit.
- Strong and highly extracted (top right) was the most bitter and astringent, with roasted notes.
- Lighter and moderately extracted (bottom left) carried the “sweet” impression and the least bitterness.
Drinkers split into two groups. The larger group (57%) liked lighter coffees best, with peak liking at around 18% extraction, and mostly disliked bitterness and sourness. The other group (43%) liked two very different styles equally: bright, fruity cups that were stronger and less extracted, and roasty, dark-chocolate cups at higher extraction. In other words, there isn’t one perfect cup. There’s the cup you like, and the chart shows how to get there.
One more finding: the “sweetness” people taste in black coffee is mostly an impression from aroma and from the absence of bitterness. Brewed coffee has very little actual sugar. That’s why a less bitter cup tastes sweeter.
How to measure TDS
TDS is measured with a coffee refractometer, which reads how much the liquid bends light. Coffee refractometers show readings to 0.01%, though accuracy varies by model, so compare readings from the same device. Readings are only as good as your sample, so:
- Zero the refractometer with distilled water at room temperature before each session.
- Stir the whole brew before sampling. Coffee from the start and end of a pour over has very different strengths.
- Cool the sample to room temperature, in a covered cup or pipette so it doesn’t evaporate and read high.
- Filter espresso and French press samples with a syringe filter. Undissolved fines and oils make the reading too high.
- Read two or three times and use the average. Clean and dry the lens between readings.
No refractometer? You can still use the ideas. Fix your ratio first (strength), then adjust the grind by taste (extraction): sour and thin means extract more, bitter and dry means extract less. Our brew guides give tested ratios and grinds to start from.
How to use your numbers
| Your result | What to change |
|---|---|
| Extraction under 18% | Grind finer, or brew a little longer or hotter |
| Extraction over 22% | Grind coarser, or shorten the brew |
| TDS too low, extraction fine | Use more coffee for the same water (shorter ratio) |
| TDS too high, extraction fine | Use less coffee, or top the cup up with hot water |
| Numbers on target but you don’t like it | Move towards the flavour you want on the 2023 chart |
| French press stuck below 18% | Steep longer and stir: it may not have finished extracting |
Immersion is different. A 2021 UC Davis study of full-immersion brews found that, once the brew reached equilibrium, extraction settled at about 21% across a wide range of ratios. Brew temperature (from 80 °C to 99 °C) and grind size mostly changed how fast it got there, not where it ended up. So if a French press reads low, the fix is usually more time, not a finer grind. Strength in immersion is almost entirely set by the ratio.
Espresso TDS and extraction
Espresso uses the same formula with very different numbers. It’s 6–10 times stronger than filter coffee. A typical 1:2 shot (18 g in, 36 g out) at 18–22% extraction reads about 9–11% TDS. Ristrettos run stronger, lungos weaker, so 8–12% TDS is the usual working range for espresso.
Two cautions from the research. First, finer isn’t always more extracted. A 2020 study in Matter found that extraction peaks at a certain grind and drops when the grind gets too fine, because water channels through the puck instead of through all the coffee. Second, the same number can taste different. The same study notes that two 22% shots pulled at different grind settings don’t share the same chemistry. Use the numbers to stay consistent, and taste to decide.
How the calculator works
- Brewed coffee weighed (pour over, drip, espresso): extraction = brewed coffee × TDS ÷ coffee.
- Water weighed, pour over or drip: it subtracts the 2.1 g of liquid each gram of grounds holds back, then works out extraction from the rest.
- Immersion: it counts all the water, because the liquid in the grounds is as strong as the cup.
- The chart shows the classic target box (green), the brew-ratio lines and your brew (orange dot). The flavour hint below it comes from the 2023 chart, which was built on drip coffee, so it’s shown for filter and immersion only.
- Your last entries are saved in your browser, so you can come back after the next brew.
Extraction and TDS FAQ
18–22% is the classic target for filter coffee and espresso. It’s the extraction range of the Specialty Coffee Association’s brewing control chart. Below about 18% coffee tends to taste sour and thin; above about 22% it tends to taste bitter and dry. Research from UC Davis in 2023 found that many drinkers prefer cups at the lower end, around 18%.
For filter coffee, 1.15–1.35% TDS is the classic target, the strength of the Golden Cup standard. Espresso is much stronger, usually around 8–12% TDS. Within those ranges, strength is a matter of taste: change the ratio of coffee to water to move it.
Multiply the weight of the brewed coffee by its TDS and divide by the weight of the dry coffee. For example, 220 g of pour over at 1.35% TDS made with 15 g of coffee is 220 × 1.35 ÷ 15 = 19.8%. For immersion brews like a French press, use the water weight instead, because the liquid left in the grounds is as strong as the cup.
No. A refractometer measures what your tongue already notices, and helps you repeat or fix a recipe precisely. Without one, set your strength with a consistent coffee-to-water ratio, then adjust the grind by taste: grind finer if the coffee is sour, coarser if it’s bitter.
Strength (TDS) is how concentrated the drink is: how much coffee is dissolved in the water. Extraction is how much of the coffee grounds you dissolved. Strength is set mostly by the ratio of coffee to water. Extraction is set by grind size, brew time, water temperature and agitation.
Most espresso measures about 8–12% TDS. A 1:2 shot (for example 18 g in, 36 g out) at 18–22% extraction reads roughly 9–11%. Ristrettos are stronger and lungos weaker. Filter the sample before measuring, because fines and oils make espresso read high.
Usually because it hasn’t finished extracting. A 2021 UC Davis study found that full-immersion brews settle at about 21% extraction once they reach equilibrium, whatever the ratio, and that grind and temperature mostly change how fast they get there. Steep longer and stir, and check that the sample was filtered and cooled before measuring.
Sources
- Guinard, Frost, Batali, Cotter, Lim and Ristenpart, A new Coffee Brewing Control Chart relating sensory properties and consumer liking to brew strength, extraction yield, and brew ratio, Journal of Food Science, 2023.
- Liang, Chan and Ristenpart, An equilibrium desorption model for the strength and extraction yield of full immersion brewed coffee, Scientific Reports, 2021.
- Cameron et al., Systematically Improving Espresso: Insights from Mathematical Modeling and Experiment, Matter, 2020.
- Specialty Coffee Association (Europe), Coffee Basics: the Coffee Brewing Control Chart (1.15–1.35% strength, 18–22% extraction).
- Specialty Coffee Association, Coffee Standards (Golden Cup: 1.15–1.35% TDS, 18–22% extraction).
- Lockhart, The Soluble Solids in Beverage Coffee as an Index to Cup Quality, Coffee Brewing Institute, 1957 (the original control chart; cited via Guinard et al.).
- Ristenpart and Kuhl, The Design of Coffee: An Engineering Approach, 2021 (liquid retained by spent grounds, about 2.1 g per g).
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