Moka Pot Grind Size: The Setting to Start From on Your Grinder

The right moka pot grind size is medium-fine: finer than you'd use for drip or pour-over, but clearly coarser than espresso. Fill the basket loosely and level, never tamped, and start from your grinder's moka setting in the table below.

That's the whole answer. The rest of this page is about why espresso-fine is the most common mistake, how to find the spot on your own grinder, and how to correct from there by taste. For the full brewing method (water, heat, timing), see the moka pot guide.

What moka pot grind looks like

Think of the space between two familiar grinds. Drip coffee is gritty and sandy, and the particles are easy to see one by one. Espresso is close to powder. It clumps when you pinch it and sticks to your fingers. Moka grind sits between the two, nearer espresso than drip. It should still feel gritty when you rub it, and it should pour freely rather than clump.

Bialetti, which makes the Moka Express, says the grind for a moka "must have a medium grain, coarser than the blend for espresso." Its product page puts it more bluntly: the coffee "must be Moka-ground, and not too fine." Perfect Daily Grind's moka guide agrees. It recommends starting at "a medium to fine grind size," coarser than pour-over but not as fine as espresso.

If you want numbers for the neighbors: published particle sizes put espresso at 250–400 µm and drip at 750–900 µm (where these figures come from). Moka falls between them, toward the espresso end. BrewMark only quotes micron bands that more than one source agrees on, and moka isn't one of them, so this page gives a description and grinder settings instead.

Why too fine is a problem in a moka pot

A moka pot isn't a weak espresso machine. Steam pressure in the bottom chamber pushes water up through the coffee bed. That only works if water can actually get through.

It blocks the flow, and the valve opens. Bialetti's page on the safety valve says the valve stays closed in normal use and opens when water can't pass through the filter and pressure in the bottom chamber climbs. It lists three causes: "the coffee is ground too finely," "the coffee has been excessively pressed into the filter," and "the temperature of the heat source is too high." If your valve hisses or spits during a brew, grind coarser before you change anything else. Bialetti also says limescale can block the valve's hole, so it recommends moving the little piston along its axis whenever you wash the pot.

It tastes bitter and burnt. Perfect Daily Grind's moka guide says that "using a grind size that is fine enough for espresso will lead to over-extraction and a bitter cup." Bialetti warns that a too-fine grind makes it hard for water to get through, which "could lead to a burnt, bad-tasting coffee."

It leaves sludge. Bialetti's check is simple: swirl the cup before you drink. If "there is an abundant residue of powder on the bottom, it means that the mixture was too fine."

Don't tamp it either. Tamping does the same damage as grinding too fine. Bialetti says to fill the funnel "up to the edge" and "do not press it down." Perfect Daily Grind adds that in a moka pot tamping "causes channelling," which leads to under-extraction. Level the basket with a finger and leave it loose.

How to find moka grind on your grinder

You don't need to hunt from scratch. Most grinder makers publish a chart, and moka is usually listed between espresso and AeroPress or pour-over.

1. Find your grinder's moka setting. Look up your model in the table below, or on its settings chart. If it's not listed, use the grind converter to carry a setting over from a grinder you know.
2. Check your zero. Hand grinders count clicks from fully closed. Close the burrs gently until they just touch, then count out. If you've never done this, read about the zero point and how to calibrate a grinder.
3. Brew once, as written. Use your usual method from the moka pot guide and don't change two things at once.
4. Taste, then move in small steps. Use one or two clicks on a hand grinder, or a single number on a stepped electric. The troubleshooting section below tells you which way to go.

If you use a moka pot and an espresso machine on the same grinder, write down both settings. They're close on the dial and easy to mix up.

Starting settings on popular grinders

These are the moka rows from each grinder's settings page. Every one listed here comes from the maker's own chart.

Starting points from each maker's own chart, collected on BrewMark's settings pages. Every grinder drifts; adjust by taste.

A few popular grinders don't have a moka figure from their maker. Their settings pages show an estimated moka point, fitted to the same dial as the maker's other settings: the Baratza Encore at 11, the Baratza Virtuoso+ at 11, the Fellow Ode Gen 2 at 3, and the Timemore C2 at 12 clicks. Treat those as rougher guesses than the table.

To see every method on one page, use the master grind size chart. If you're still choosing a grinder and moka is your main brew, the grinder finder for moka pots ranks the options for it.

Troubleshooting by taste

Taste the coffee before you add milk or sugar. Then change one thing at a time.

Bitter, harsh or burnt. This is the most common moka complaint. Grind one or two steps coarser. If it's still bitter, look at heat before grind. Perfect Daily Grind lists high heat as a common mistake and recommends medium-low. It also says to take the pot off the stove "once it starts making bubbling noises." Leaving it on until the end "is a sure-fire way to burn your coffee." More fixes are in how to fix bitter coffee.

Sour, thin or weak. Grind a step finer. Make sure the basket is full to the rim and level, because a half-full basket lets water rush through. If it still tastes sharp and hollow, see how to fix sour coffee.

Watery. Check the water level before the grind. Bialetti says not to fill past the safety valve "or the coffee might be too watery."

Valve hisses, or coffee barely trickles. Grind coarser, make sure the basket isn't packed, and turn the heat down. Those are the three causes Bialetti names. If the valve vents even with a coarser, loose bed, clean it and check the filter plate holes for blockages.

Gritty sludge in the cup. The grind is too fine, or the grinder makes a lot of fines. Go a step coarser first.

Good one day, off the next. A new bag of beans can need a small change. See how to adjust grind for a new bag.

Next steps

• Find your grinder's full chart in the grinder settings hub, or compare methods side by side on the master grind size chart.
• Brew it with James Hoffmann's moka pot method, or follow the step-by-step moka pot guide.
• Moving to a new grinder? Convert your settings between grinders so you don't start from zero.
• Shopping for a grinder that handles moka well? Start with the finder, set to moka pot.