For siphon coffee, grind your fair-trade beans medium-fine, about the texture of coarse sand or kosher salt. That is slightly finer than a typical pour-over grind but well coarser than espresso. Blue Bottle Coffee’s siphon brew guide describes the target as medium-fine, similar to sea salt, with a total brew time of about 1:30 to 2:00 minutes. The fair-trade label itself does not change the grind, since it certifies pricing and farming practices, not the bean’s size or roast level. What actually drives your setting is the roast level, bean density, and the filter inside your siphon.
The Baseline Grind: Medium-Fine, Like Coarse Sand
According to Blue Bottle Coffee’s siphon preparation guide, the starting point is a medium-fine grind. Texture is the easiest field check: think coarse sand or kosher salt, not powder. Hario, the leading siphon manufacturer, gives the same direction in its operating guidance for the Technica and Sommelier brewers. Their manuals state that a grind which is too fine will clog the cloth filter and prevent the brewed coffee from returning cleanly to the lower bowl.
James Hoffmann, author of The World Atlas of Coffee, describes the balance siphon brewing requires. Too fine a grind causes the drawdown to stall as the coffee bed compacts under vacuum pressure. Too coarse produces a watery, under-extracted cup because the contact time is short, roughly one minute.
A burr grinder matters more than the exact setting here. Blade grinders chop beans unevenly, which creates a mix of dust and boulders that behaves unpredictably under vacuum pressure. A burr grinder with adjustable settings lets you move one small step at a time when dialing in.
Adjusting for Your Fair-Trade Coffee’s Roast Level
Fair-trade certification guarantees a minimum price and social premium for farmers. It does not tell you the variety, altitude, or roast level of the beans in the bag, so the grind has to follow the coffee, not the label.
Dense, lightly roasted, high-altitude single origins, such as Ethiopian or Colombian fair-trade lots, extract more slowly. A medium-fine grind exposes enough surface area to get proper extraction during the short immersion phase.
Darker roasted fair-trade blends are more porous and extract faster. Going slightly coarser, toward a true medium, helps prevent bitterness and ashy flavors. If your bag does not state a roast level, email the roaster or start at medium-fine and let taste guide you.
Match Your Grind to Your Siphon’s Filter
The filter inside your siphon changes the grind it wants. Most backyard siphons ship with a cloth filter, which is the traditional standard.
Cloth filters trap nearly all micro-fines while letting aromatic oils pass. Keep the grind at medium-fine and avoid anything powdery so the weave does not choke during drawdown. The standard cloth filter replacements from Hario fit most Technica and Nouveau models.
Paper filters drain more slowly than cloth and give a cleaner cup. Go slightly coarser, around a true medium, and aim for a total drawdown under about a minute. Metal mesh filters let more insoluble solids into the cup, so a medium-coarse grind keeps sediment out of the lower chamber.
Use the table below to pick a starting grind based on your filter and coffee profile, then adjust one step at a time by taste.
| Setup | Starting Grind | Texture Reference |
|---|---|---|
| Cloth filter, light-to-medium roast single origin | Medium-fine | Coarse sand to kosher salt |
| Cloth filter, dark roast blend | Medium to medium-fine | Slightly coarser than coarse sand |
| Paper filter, any coffee | Medium | Coarse sand |
| Metal mesh filter, any coffee | Medium-coarse | Noticeably gritty, like rough sand |
Dialing In by Taste and Drawdown Time
Your first brews are information gathering, not failure. The vacuum drawdown after you remove the heat is the clearest signal your grinder gives you.
If drawdown takes longer than about 45 to 60 seconds or stalls completely, the grind is too fine and excess fines are choking the filter. Blue Bottle’s guide flags the same threshold: if drawdown runs past roughly 45 seconds, adjust coarser to avoid clogging the cloth filter.
If drawdown finishes in well under half a minute and the cup tastes sour or weak, water is channeling through gaps between big particles. Move the grind finer.
If the brew tastes bitter, dry, or astringent, that can indicate over-extraction. Coarsen the grind slightly or reduce agitation during the steep.
If you experiment with espresso-fine or Turkish-fine grinds out of curiosity, expect a stalled siphon, and expect a very different result. And whether you use this brewer or an AeroPress with the same fair-trade beans, one variable at a time is the only dialing-in method that actually works.
A Suggested Recipe to Test Your Grind
A grind setting only proves itself in a full brew. This starting recipe, adapted from Blue Bottle’s siphon guide, gives your medium-fine setting a fair test.
Use a 1:15 to 1:16 ratio, for example 20 grams of coffee to 300 to 320 grams of water. Water in the upper chamber should stabilize between 195°F and 202°F (90.5°C to 94.5°C) before you add the grounds. Steep for about 60 seconds with gentle agitation at the start and again at the halfway point, remove the heat, and let the vacuum pull the brew down over 30 to 50 seconds.
A small scale that reads to 0.1 grams makes the ratio repeatable, which is the only way to know whether a taste change came from the grind or from the dose.
Freshness changes extraction too. Degassed, freshly roasted beans behave differently from beans a month past roast, a detail covered in our guide to fair-trade coffee freshness for siphon brewing.
Common Mistakes to Avoid
Grinding espresso-fine “for strength” is the most common siphon error. The vacuum cannot pull water through acompacted bed of powder, and you get a stall or a muddy, bitter cup.
Blade grinders introduce the same problem from a different direction. Their uneven particle mix means part of the coffee extracts fast while part of it barely extracts at all, which no filter change can fix.
Reuse of a dirty cloth filter will masquerade as a grind problem if you have not kept it clean. And for reference to the wider family, if your fair-trade beans also get brewed as drip coffee, that method takes a very different setting than siphon does.
Conclusion
Start your fair-trade coffee at a medium-fine grind, roughly the texture of coarse sand or kosher salt, with a target drawdown of 30 to 50 seconds after removing the heat. Brew one test batch at a 1:15 ratio, then adjust one grinder step at a time based on taste, finer for sour and weak or coarser for bitter and slow. Keep notes on each change and your siphon will repay the attention.