Coffee Grind Size Chart: The Right Grind for Every Coffee Machine

If you have ever made a coffee at home that tasted bitter, sour or simply flat, there is a good chance the beans were not the problem. In most cases, the culprit is grind size. The coarseness or fineness of your coffee grounds has a bigger influence on flavour than almost any other factor in home brewing, yet it is the one most people overlook.

In this guide, we explain what grind size actually does, share a coffee grind size chart you can refer back to and show you how to diagnose common brewing problems that come down to nothing more than the wrong grounds.

Brewing coffee is a process called extraction. Hot water passes through or sits with your coffee grounds and dissolves the compounds that give coffee its flavour, including acids, sugars, oils and aromatics. How quickly and evenly that happens depends on the surface area of the grounds, which is determined by how finely they are ground.

Finer grounds have more surface area, so water extracts flavour from them quickly. Coarser grounds have less surface area, so extraction takes longer. The goal is to match your grind size to the contact time of your brewing method:

• Short contact time needs a fine grind: Espresso forces water through the coffee in around 25 to 30 seconds, so the grounds must be fine enough to give up their flavour almost instantly.
• Medium contact time needs a medium to medium-coarse grind: Filter coffee brews over several minutes as water drips through the bed of grounds, so a medium-coarse grind extracts steadily without over or under doing it.
• Long contact time needs a coarse grind: French press coffee steeps for around four minutes in direct contact with water, so coarse grounds prevent the brew from becoming harsh and muddy.

Get this balance wrong in either direction and the results are noticeable. Grounds that are too fine for the method over-extract, pulling out bitter, astringent compounds. Grounds that are too coarse under-extract, leaving the coffee weak, sour and thin.

Use this chart as your starting point, then read on for the detail behind each brewing method:

These should be considered as a starting point rather than a rigid rule. The beans, roast level and personal taste all play a part, which is why having the ability to adjust your grind in small increments is so important. The sections below explain how to fine-tune from here.

Click here for a downloadable pdf of the below chart

Coffee grinds are usually described on a scale from extra fine to extra coarse. Here is how the seven main categories break down and what each is used for:

Extra fine (similar to flour)

Reserved for Turkish coffee, where powder-like grounds are simmered directly in the water rather than filtered out, creating that method’s characteristically thick, intense brew.

Fine (similar to fine salt)

The standard for espresso machines. Fine grounds create resistance against pressurised water, which is what produces a concentrated shot with a rich crema.

Medium-fine (similar to table salt)

Suits manual pour over brewers such as the V60 and Kalita Wave, where water passes through the cone relatively quickly and a slightly finer grind keeps extraction on pace.

Medium (similar to regular sand)

The go-to for the Aeropress, where a short steep followed by pressure from the plunger suits a middle-of-the-road grind. It is also a sensible starting point for experimenting with hybrid methods.

Medium-coarse (similar to rough sand)

The sweet spot for filter coffee machines and drip brewers. Water flows through the bed of grounds at the right pace over a four to six minute brew cycle for a balanced, aromatic cup.

Coarse (similar to sea salt)

The correct choice for French press, where grounds sit in direct contact with water for around four minutes and need to stay behind the mesh plunger.

Extra coarse (similar to peppercorns)

Best for cold brew, where the extremely long steep of 12 to 24 hours would turn anything finer harsh and over-extracted.

Espresso is the least forgiving brewing method when it comes to grind size. A pump-driven espresso machine, such as the CASO Design EspressoGourmet, pushes water through a compacted bed of coffee at high pressure, with its 19 bar pump generating the force needed for proper extraction.

Because the water is only in contact with the coffee for around 25 to 30 seconds, the grind must be fine enough to slow the water down and let extraction happen. If the grind is too coarse, water races through the portafilter, producing a pale, watery shot with no crema. If it is too fine, the water struggles to pass through at all, the shot drips out slowly and the result is intensely bitter.

A useful reference point is the pressure gauge. The EspressoGourmet includes a front-mounted analogue manometer, which shows you the brewing pressure in real time. If the needle sits low during extraction, your grind is likely too coarse. If it climbs too high, the grind is too fine. Watching the gauge while adjusting your grind one setting at a time is the fastest way to dial in a consistent shot.

Pre-ground supermarket coffee labelled “espresso grind” can work, but it is a compromise. Ground coffee begins losing its aromatics within minutes of grinding, and a one-size-fits-all grind cannot be adjusted to suit your specific machine, beans or taste.

Filter coffee machines require much coarser coffee, calling for a medium-coarse grind, roughly the texture of rough sand. Water drips through the grounds over four to six minutes, so the grind needs to allow a steady, even flow without over-extracting during the longer brew cycle.

Evenness matters just as much as size here. If your grounds contain a mix of fine dust and large chunks, the fine particles over-extract and turn bitter while the large ones under-extract and taste sour, leaving you with a confused, muddled cup. This is one of the main weaknesses of cheap blade grinders, which chop beans into wildly inconsistent particle sizes.

The machine itself plays a part too. The CASO Design Aroma Sense filter coffee machine brews at a controlled 92 to 96 degrees Celsius, the temperature range widely recognised as ideal for extraction, and uses a 9-hole brew arm to saturate the entire bed of grounds evenly rather than pouring water through the centre. With a consistent medium-coarse grind and even saturation working together, every particle extracts at the same rate, which is exactly what a balanced filter coffee needs. Its reusable titanium-coated stainless steel filter also means no paper filters, and metal filters allow slightly more of the coffee’s natural oils through, giving a fuller-bodied cup.

If your filter coffee regularly tastes bitter, try a slightly coarser grind. If it tastes weak or sour, go slightly finer.

At the coarse end of the spectrum, French press and cold brew both involve long, full-immersion contact between water and coffee. A coarse grind, similar in texture to sea salt flakes, extracts slowly and evenly over the four-minute steep of a French press. Cold brew goes a step further still, with an extra coarse grind closer to rough peppercorns standing up to a steep of 12 hours or more without turning harsh.

Coarse grounds also matter for practical reasons. A French press relies on a mesh plunger to separate grounds from the finished coffee, and fine particles slip straight through it, leaving sediment at the bottom of your cup and a gritty texture. If your French press coffee is muddy or bitter, the grind is almost certainly too fine.

Everything above depends on one thing: being able to produce the right grind size consistently. This is where the type of grinder matters.Blade grinders smash beans with a spinning blade, producing an uncontrolled mix of powder and chunks. Burr grinders crush beans between two precisely spaced grinding surfaces, so every particle comes out at the size you have selected.The CASO Design BaristaChef Inox is a conical burr grinder with 48 grind settings spanning the full spectrum from espresso to French press, so a single grinder covers every machine in your kitchen. The BaristaChef has features to enable you to create great quality coffee:

• Slow grinding protects flavour: The stainless steel burrs spin at a slower 450 rpm, which minimises heat build-up during grinding and protects the delicate aromatic compounds that high-speed grinders can burn off.
• Precise settings for dialling in: With 48 settings to choose from, you can make the small single-step adjustments needed to fine-tune an espresso shot or correct a bitter filter brew.
• Grind straight into a portafilter: A modular portafilter holder lets espresso drinkers grind directly into the basket, keeping the workflow tidy and the dose fresh.
• Fresh grounds every time: Dosing by cup, timer or manual control means you grind only what you need, when you need it, rather than letting pre-ground coffee go stale.

Whichever grinder you use, the principle is the same. Grinding fresh, to the correct size for your brewing method, will do more for your coffee than upgrading your beans, your water or your machine.

• Bitter, harsh or astringent: Over-extraction. Your grind is too fine for the method. Go one or two settings coarser.
• Sour, weak or watery: Under-extraction. Your grind is too coarse. Go one or two settings finer.
• Espresso with no crema: The grind is too coarse or the coffee is stale. Grind finer and use freshly ground beans.
• Sediment in your French press: The grind is too fine for the mesh filter. Switch to a proper coarse grind.
• Inconsistent results day to day: Uneven particle sizes, usually from a blade grinder or old pre-ground coffee. A burr grinder with fresh beans solves both.

Grind size is not a detail. It is the mechanism that controls how flavour gets from the bean into your cup, and matching it to your brewing method is the single most effective change most people can make to their home coffee. Fine for espresso, medium-coarse for filter, coarse for French press, and always as freshly ground as possible.

Explore the full CASO Design coffee range to find the right combination of grinder and machine for the way you drink coffee.