For medium-roast coffee in a siphon, grind medium-fine, a texture close to table salt and just a step finer than a drip setting.
The Specialty Coffee Association’s brewing handbook places full immersion with vacuum filtration in a 500 to 700 micron particle band.
James Hoffmann, World Barista Champion and author of The World Atlas of Coffee, recommends medium-fine for vacuum pots, close to a pour-over grind.
Medium roast fits this setting with room to either side. Keep reading to see the texture check, filter adjustments, taste troubleshooting, and exact dial numbers.
Why the Vacuum Drawdown Sets Your Grind
A siphon brews by full immersion: every ground steeps in all of the water at once. Then vacuum pressure pulls the finished brew down through the filter into the lower globe.
That pull, called the drawdown, is what your grind size has to cooperate with.
Finer particles expose more surface area, so near-boiling water extracts flavor from them quickly.
The same fine particles resist the pull, though. Hoffmann warns that grinding too fine for a vacuum pot stalls the return flow and produces bitterness.
Grind size is also the lever that moves extraction yield, the share of each bean that ends up dissolved in your cup. The SCA’s extraction yield target runs 18 to 22 percent.
Heat is part of the story: a siphon sends water up at or near a full boil, so the immersion phase runs hot.
Medium roast handles that heat well and dissolves steadily, so medium-fine works as the natural default. For a cleaner, brighter cup, ease slightly coarser; for extra body and sweetness, edge slightly finer.
Next comes the texture check that tells you whether your grinder is close.
What Medium-Fine Looks and Feels Like
Siphon grounds for medium roast should look like coarse sand and feel like table salt between your fingers.
Grind advice comes in two forms: a particle texture and a dial number, and dial numbers differ from grinder to grinder. Learn the texture first, then translate it to your gear with the table below.
Blue Bottle’s siphon brew guide calls for coffee ground to a texture resembling table salt.
For contrast, that is slightly finer than a drip or pour-over grind and clearly finer than the coarse crumbs of French press.
A traditional pick for this method is the Hario Technica syphon, and Hario spells syphon with a y.
- Key Specifications:
- Brewer type: vacuum siphon
- Body material: heat-resistant glass
- Filter: reusable cloth
- Heat source: alcohol burner or halogen beam heater
A quick pinch test before you brew catches a wrong setting while it is still cheap to fix.
Match the Grind to Your Filter
Your siphon’s filter decides how fine you can grind before the drawdown suffers.
Cloth, the traditional filter, holds back fine particles well, so it tolerates the finest grind of the three.
Hoffmann puts that tolerance to work: with a clean cloth filter, he runs slightly finer than his standard pour-over target for vacuum pots.
Paper filters can choke once fines settle against them, so start a touch coarser than you would with cloth.
Metal mesh and glass rod filters let fine dust pass straight into the cup, so a medium to medium-coarse grind keeps sediment and bitterness out.
Use the table below to pick a starting grind for your siphon’s filter type.
| Filter | Starting grind | Why it works |
|---|---|---|
| Cloth (traditional) | Medium-fine | Holds back fines, so it tolerates a slightly finer grind for body and sweetness |
| Paper adaptor | Medium | Can choke when fines settle, so run one touch coarser than cloth |
| Metal mesh or glass rod | Medium to medium-coarse | Lets fine dust pass through, so a coarser grind protects the cup |
From that starting point, taste and flow take over.
Dial It In by Taste and Drawdown
Two signals guide every grind move you make: how fast the coffee pulls down, and how the cup tastes.
Hold everything else steady while you dial.
Blue Bottle’s method keeps a 20 gram dose in the pot with a 40 to 60 second contact time before the flame comes off. Copy that recipe and the grind becomes your only moving part.
Change two things at once and the result tells you nothing about either one. One move per brew is how a siphon gets dialed quickly.
If the cup still tastes flat once the drawdown looks right, the beans may be past their best window. Check how fresh your beans should be before chasing the problem with a finer grind.
Use the table below to diagnose your cup and choose your next grind move.
| What you notice | Likely cause | What to do |
|---|---|---|
| Drawdown stalls or runs much slower than earlier brews, and the cup turns bitter or muddy | Grind probably too fine | Move one step coarser |
| Drawdown finishes much faster, and the cup tastes weak or sour | Grind probably too coarse | Move one step finer and stir so all grounds get wet evenly |
| The cup leaves a harsh, drying finish | Often points to over-extraction, from a grind slightly too fine or a contact slightly too long | Move a touch coarser or end the contact sooner |
| Smooth drawdown, but the cup is thin with little body | Extraction is probably running a little short | Try a slightly finer grind for more body and sweetness |
Once taste and flow agree, you can set the same answer onto any burr grinder.
Starting Settings for Common Burr Grinders
Start from your pour-over setting and move one small step finer, then judge every further change by taste.
A burr grinder earns its keep here because it repeats the same particle size at the same dial number.
An entry-level option with numbered steps is the Baratza Encore.
- Key Specifications:
- Burr style: conical steel burr
- Settings: 40 numbered steps
- Class: entry-level electric grinder
Use the table below to set your burr grinder for a first siphon brew.
| Grinder | Suggested starting setting | Grinder type |
|---|---|---|
| Comandante C40 | 18 to 22 clicks | Hand grinder |
| Baratza Encore / Virtuoso+ | 13 to 16 | Electric, conical burrs |
| Fellow Ode Gen 2 | 3.1 to 4.2 | Electric, flat burrs |
| 1Zpresso JX-Pro | 2.2.0 to 2.6.0 | Hand grinder |
Treat every number in that table as a first-brew guess rather than a rule. Burrs wear, bean density varies, and roasters use the medium label loosely.
Siphon settings belong to the siphon alone. If your medium roast also heads into a drip machine, give it a separate grind dial-in for drip coffee.
Set the dial, brew one cup, read the drawdown, and let taste call your next move.
For medium roast in a siphon, grind medium-fine: table-salt texture, slightly finer than drip, inside the SCA’s 500 to 700 micron band.
Brew a 20 gram dose at that setting, watch for a smooth drawdown, and move the dial one small step at a time as taste asks. Fresh beans plus a fixed recipe are all the rest a siphon needs.