Grind size and extraction

The basics

• Finer grounds expose more surface and extract more readily, and coarser grounds extract less 5:33 0:32. Coarser grinds also leave wider gaps so water flows faster, and finer grinds slow it 12:24.
• Grinding and the particle distribution are the most influential extraction variable according to Dr Samo Smrke, ahead of temperature, then even-extraction technique 16:53.
• Ratio is the other big lever. In espresso, adding even 5 to 10 g of yield changes extraction more than a degree or two of temperature 1:32, and Lance Hedrick calls ratio the main driver of extraction yield 7:13. A longer pour-over ratio (1:17 rather than 1:15) gives lower strength but higher extraction at the same grind 5:09. Grind size still sets the baseline 18:27.

Finer is not always more extraction

• The "volcano". Plot extraction against grind and you get a volcano. Starting very fine, yield climbs as you open up, levels off, then drops once you go too coarse. A fairly coarse setting can therefore equal a very fine one 6:37.
• Very fine espresso grinds channel. Water takes the easiest paths, so some regions stay badly under-extracted while the refractometer only reports the average 10:10 11:10. Past a point, finer adds resistance and extraction can fall 12:47.
• Over-fine grinds can even run faster, because coffee is hydrophobic and clumps more as it gets finer 29:36. Channelling gives bitter spots alongside sour ones 6:13 22:52.
• Coarser grinds flow more evenly, are more repeatable, make puck prep a bit less critical and allow lower doses 13:42. Shot time is a result of the grind. A coarser grind can reach equal or higher extraction faster 8:37.

What extraction yield buys you

• Flavours arrive in order, with sour and salty acids first, then sweetness, then bitter, drying compounds 1:31. Acids are small and soluble, while bitter compounds such as chlorogenic acid lactones arrive later 7:40.
• Most of the acids (about 80 to 90%) have already dissolved by around 15 to 20% extraction, so pushing to 25% for acidity is misguided. Extra yield mostly adds bitterness and astringency 13:18. Past about 19 to 20%, the pleasant floral and fruity compounds plateau while bitter, rubbery and roasty ones keep building 8:36 6:19.
• Small particles, high temperature and long contact all favour bitter extraction. Better grinders let you reach higher yields before that shows, but they can't remove bitter compounds 8:44. Because bitterness masks aroma and acidity, high-extraction cups taste muted 15:20.

Lance Hedrick's extraction targets (they drifted lower)

Lance Hedrick's grind-size test (April 2026)

Lance Hedrick brewed five pour-overs on a Zerno Z1 at 750, 700, 650, 600 and 550 µm with everything else fixed, and extraction rose from about 20.1% to 22.2%. The coarsest was the most vibrant, and the cups at 600 and 550 µm were bitter and muted, with the jump between 650 and 600 8:52. A 50 µm step made a modest difference and 100 µm a big one. He likens 50 µm to about 3 °C of water temperature 10:52. For him, a finer grind adds less bitterness than 3 °C hotter water, so he brews at 91 to 93 °C and moves extraction with grind, agitation or pour count instead 11:22. Longer contact from finer grinding also mutes volatile aromas 12:23.

Burrs change the relationship

• Different burr geometries gave 22.9% and 18.7% extraction at the same visual grind and drawdown 6:38. Two grinders at the same size drained 15 s apart yet gave near-identical TDS 9:44.
• Recipes don't transfer between grinders because their distributions differ, so treat any recipe as a baseline 7:10. Comparing burrs at equal grind size, TDS or yield is misleading because each has its own sweet-spot window 7:12. One fines-heavy burr needed grinding 80 to 100 µm coarser and still drained about 20 s slower 8:14.
• Low-fines burrs let you push extraction further before astringency 13:15. The ZP6 Special went to about 23 to 23.5% 23:24, and Timemore Turbo burrs to 23 to 24% where multi-purpose burrs stopped around 21 to 22% 3:04. Fines-heavy burrs turn astringent when pushed and work better coarser at lower extraction 19:13. Comandante/K-series style burrs give complexity at lower extraction but fall off near 24 to 25% 4:04. SSP Cast burrs turned bitter and astringent at about 23 to 23.5% 7:09.
• Removing fines always lowered measured extraction 16:22.

Roast, process and coffee

• Dark roasts need coarser settings than light ones 9:49 22:06. At the same setting a dark roast grinds to a peak about 100 µm smaller, so moving from light to dark at an unchanged setting slows shots 22:28.
• Light roasts need finer because they're denser and less soluble and make fewer fines 8:15 21:28 36:41. They also hold together less well in the puck and vary more shot to shot 21:28.
• Roasting expands the cell structure, so darker is more soluble 8:38. Dense, high-grown and heirloom coffees are harder to extract. Low-density varieties such as Pacamara and Maragogipe extract easily, and peaberries are dense 27:04 5:35. The funkier the process (washed → honey → natural → anaerobic), the more soluble 7:06.
• Darker, brittle roasts grind more easily at very fine settings 0:00. Decaf grinds finer at the same setting 39:38.

Quick grind checks (Lance Hedrick's advice changed)

• In December 2022, Lance Hedrick said ground espresso should feel powdery and hold a fingerprint when pinched. A gritty, sandy sound means go finer 4:44.
• By August 2023 it should hold a small peak and a fingerprint, but not be so powdery it balls up or so coarse it feels like sugar-substitute granules 2:05.
• By June 2025 the cue had reversed. Visible fingerprints mean too fine and powdery, and you want a gritty, sandy sound 6:44. This matches his later push to start espresso coarse.

Immersion and pressure brewers

• Pressed gently, a French press had to be ground far finer than Lance Hedrick expected to keep up with other brewers 9:31. The Weber Bird can brew very coarse at 1:15 to 1:16 and stay clean 7:01. With a mesh filter alone too coarse a grind gives too little resistance, so add paper 12:31.

James Hoffmann's view

• Grind is the main dial. For pour-over James Hoffmann adjusts extraction mainly through grind. He goes finer until a sudden wall of bitterness and astringency appears, then steps back 10:45 9:48. Many people struggling with V60 grind too coarse, and light roasts need finer 1:32.
• The curve. Taste improves with extraction up to a point, then drops sharply 1:32. In espresso you generally want to grind as fine as possible until the puck channels. Bitterness from too fine is usually localised over-extraction in channels while the whole may be under-extracted, and refractometer yields often fall at very fine settings 3:03 4:03.
• One grind change moves several things. Finer adds surface area, packs tighter, raises resistance and lengthens contact, all at once 1:02. Shot time reflects puck resistance, and the classic 25 to 30 s window works because the grind needed to hit it exposes the right surface area. Contact time itself matters less 1:30 2:31. Lowering pressure late in a shot lengthened contact without raising extraction 7:34.
• Coarser can still work with a longer ratio, giving a more even extraction but a different texture 5:04 4:35. Lower pressure (about 6 bar) with a coarser grind can extract more evenly than 9 bar 10:36.
• Roast. Darker roasts extract more easily, and light roasts need finer grinds, lower espresso doses and hotter water 5:34 2:02 1:02. Dense, high-grown washed coffees are generally harder to extract 6:04.
• Cheap grinders. Grind a little finer and brew shorter instead of going coarse, where boulders multiply 7:12.
• Method sensitivity. Grind matters most in pour-over and less in immersion like French press or AeroPress 18:28. If you use a bag within a week, brew one immersion method and can't afford a decent grinder, good pre-ground may beat a cheap grinder 19:00. Pre-ground loses sweetness within a day and turns harsh by about ten days 3:01.
• High-extraction espresso. Scott Rao's very fine, paper-filtered, low-pressure shots reached 27 to 28% and tasted light, sweet and acidic rather than bitter 4:09.

Daddy Got Coffee's view

• Compounds extract in a fixed order (sour, then sweet, then bitter). Finer grinding slows the shot and pushes towards bitter, while coarser speeds it up and pushes towards sour 1:01 7:13.
• Darker roasts, naturals, fermented coffees and decaf are more soluble, and light, washed and high-altitude coffees less so. That lets you predict direction before brewing 15:26.
• On some burrs brew time misleads. With the Kinu stock burr, going finer for pour-over raised extraction while drawdown barely changed 8:42 11:44.

Kyle Rowsell's view

• Finer isn't always more. At very fine espresso settings resistance and channelling rise, so yield can fall. A coarser grind with higher flow and lower pressure can match or beat a traditional shot in far less time 3:47 6:18. This is the same argument Lance Hedrick makes.
• A lower extraction isn't automatically worse. Kyle Rowsell's centre-pour V60 lands around 18 to 20% and still makes some coffees shine 4:37.
• AeroPress tends to run under-extracted, and a finer grind, hotter water and more time push it towards pour-over strength 0:00. Multi-pour V60 methods add agitation, so keep the grind coarse to avoid bitterness and clogging 3:11.
• Very soft tap water (around 30 ppm) can leave cups flat and under-extracted 21:40, and better beans matter more than a grinder upgrade 5:09, echoing Lance Hedrick's "coffee matters most".

The Coffee Chronicler's view

• With more water and time than espresso, pour-over often tastes better ground coarser. Washed light roasts handle a finer setting and naturals and honeys a coarser one 0:30. The Coffee Chronicler uses strength and extraction on purpose. He pushes floral light roasts to higher extraction at lower strength and keeps mediums and naturals less extracted but stronger 3:31.
• Grind and agitation interact. A finer grind gives agitation more tiny particles to dislodge, so a coarse grind cushions heavy agitation such as the 4:6 method uses 6:04. Light roasts cope with more stirring, while darker ones turn muddy and astringent 5:03.
• A strong 1:15 ratio forgives the coarser grind a modest grinder needs 2:33, but a very coarse grind still tastes thin however strong the ratio 5:34. Very uniform burrs (Eureka Filtro) tasted best ground finer, extracting around 21 to 22% instead of 19 to 20% 25:10.
• The early part of a brew carries harsh, sharp and savoury compounds, and the sweeter fruity ones come later. For anaerobic naturals he drops part of that early fraction 5:11 10:44.
• He sees maximum extraction evenness as important against espresso channelling but a misleading target for drip 5:47, which is a softer stance than Sprometheus's. He also rates water chemistry above grinder differences 7:14.

Sprometheus's view

• A yield number on its own says little about quality. Two brews at about 19% tasted completely different, and shots from 4 to 9 bar all landed within half a percent of 19% yet tasted unlike each other 4:35 5:37. That matches Lance Hedrick's later caution about yield numbers.
• Coarser can extract better because water passes more evenly 6:08. Turbo shots often still reach 18 to 19% despite brief contact, and a slightly longer hybrid reaches 20 to 21% with more texture 1:37 3:12, and winning AeroPress recipes also grind coarser than the old instructions 3:16.
• Lower brew pressure stirs the puck less and moves fewer fines, so a finer grind can hold the same shot time and possibly extract more 6:37. A blooming espresso permits a finer grind and roughly doubles brew time, extracting about 1 to 1.5% more than a straight 9-bar shot 5:59 4:27.
• In pour-over the final drips run slowly as fines block the bed and can over-extract. Pulling the dripper early avoids them, and "top and tail" brews came out about 3% lower in extraction but clearer 3:04 4:05. Sprometheus finds percolation cleaner and crisper and immersion heavier-bodied and less acidic 0:30.
• His espresso grind check is by feel. Too fine is clumpy like damp sand, barely drips and can exceed 10 bar. Too coarse looks like coarse salt or pepper, spurts and runs thin with little crema 2:07. Compare Lance Hedrick's quick grind checks above.

European Coffee Trip's view

• Espresso roasts are taken darker, and so dissolve more readily, because pressure pulls a lot out fast. Filter roasts stay lighter to keep aromatics over a two-to-four-minute brew 0:31. Because espresso extracts so much more, its acidity and bitterness are much louder 1:33.
• Drain time is the read-out. Brodie of The Nomad Barista links too slow a Chemex drain to bitterness and too fast to sourness 6:44. Martin Wölfl grinds finer (about 630 µm) with a fast paper without over-extracting 8:49.
• In immersion, the water around the grounds saturates and slows further extraction, so Gwilym Davies stirs mid-brew 4:23.
• Temperature is used alongside grind. Emi Fukahori uses 94 to 95 °C when she wants a brighter, more extracted cup and 90 to 92 °C to calm it 4:12, and Jackie Tran drops the final pour to 80 °C since most extraction has already happened 2:34.

Brian Quan's view

• Brian Quan sees two ways to reach high extraction. One is a very fine grind with few pours, which gives a blended, harmonious cup. The other is to grind coarser and agitate hard with wet WDT, which separates flavours more 4:37. Holding grind and ratio fixed, changing only agitation can make one coffee taste like two 16:59.
• Filter speed changes what grind you can use. With fast papers you can go much finer and extract more without stalling, while a slow paper takes twice as long to drain the same grind 0:31. He grinds finer with fast nonwoven filters than with ordinary paper 10:44.
• Very light roasts resist extraction but are also tough to overdo, so a very fine grind and a long brew stay free of harshness 1:33, in line with Hoffmann's advice for light roasts.
• The grinder sets the ceiling. Plenty of grinders reach 20 to 24% when pushed, but the result can taste rough, and dearer grinders keep tasting good over a wider range 11:09. On a small conical his sweet spot is about 18 to 20% 13:14, and 98 mm flats reach 26 to 27% easily, though high numbers don't guarantee a good cup 9:16. For some coffees he enjoys anything from about 21 to 25%, with the presentation shifting 5:10.
• The brewer matters too. The Orea Z1 reached about 21% with both fast and slow pours, so pour shape changed character rather than yield 15:27, and the Cafec Deep 27 seemed almost indifferent to grind size 1:33.

Bluebird Coffee Roastery's view

• A refractometer turns a brew's strength into an extraction figure. Filter typically reads near 1.4% TDS and espresso about 8 to 11% 0:35 1:06. Filter extracting only about 15 to 16% is clearly under-extracted, while pushing too far draws out unwanted material 4:08.
• A wide particle spread blurs that number. Large pieces extract more slowly than small ones, so a cup can taste confused even when the average looks right 2:36, much as Sprometheus notes that equal yields can taste different.
• Time between pours raises extraction without a finer grind 3:09. Dense washed coffees often want a coarser grind, while processed lots with broken-down structure extract easily 7:15 2:33.

Asser Christensen's grind size chart (The Coffee Chronicler website)

Asser Christensen, who founded and edits The Coffee Chronicler, keeps a grind size chart with setting ranges per grinder for French press, pour-over, AeroPress, moka and espresso. Readers submit the numbers through a form, so treat them as rough starting points, as Christensen says himself. The ranges for grinders covered here are on each grinder page, marked "Christensen". His caveats line up with the creators above:

• Grind size is only one lever. Ratio, brew time, agitation and water temperature all move extraction too.
• Budget grinders tend to make more fines than premium ones, so the same nominal setting can taste different.
• Fines-heavy coffees, light-roast Ethiopians in particular, may want a few steps coarser.
• Espresso settings drift with bean age and how full the hopper is, so dial in at home rather than copying a number.
• Pressurised baskets tolerate a coarser grind.
• For cold brew Christensen points to the French press setting.

For Notchbook

The sour/balanced/bitter tag maps onto this sequence. Sour usually means moving towards more extraction (finer, a longer ratio, hotter), and bitter-and-drying means less. Bitter can also mean channelling from grinding too fine, in which case going coarser fixes it. See troubleshooting.

Summarised in our own words from the creators' videos, with every point linked to the moment it comes from. Notchbook isn't affiliated with or endorsed by any of these creators, so please watch the originals for full context. Sources

Keep reading

• Burr alignment
• Astringency
• Conical vs flat, and burr geometry
• Particle size distribution and fines
• Retention, static and RDT
• Seasoning new burrs
• Slow feeding and RPM
• Zero point and grinder scales
• Grinder workflow: single dosing, WDT, RDT, purging and storing beans
• Troubleshooting: what to change when a cup tastes wrong

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