Remember in school when the teacher would ask you to calculate how much wrapping paper Sally would need to wrap one hundred presents, and you sat there wondering if it was lunchtime yet (or how Sally could afford that many presents)?

Well, your maths teacher kind of had a point, and that point is surface area. It’s plain inefficient to brew coffee using whole beans—there’s not enough surface area for water to filtrate through and extract the good stuff from! Any attempt would just end up with a very watery coffee.

To increase surface area, you need to break up the bean. Moreover, the bean needs to be broken into same-sized pieces to ensure an even extraction. Hence the need to grind coffee! How fine you grind the coffee beans will determine how quickly extraction will take place.

As a general rule of thumb, the finer the grind, the quicker the coffee-making process. This is why the grind size will change depending on the brewing method you choose. For example, a coarser grind works better with slower brewing methods like drip coffee, while a finer grind is necessary for a speedy espresso machine. But more on that later.

When it comes to domestic coffee grinders, there are only two types available on the market (and before you ask, yes, one is infinitely better than the other): blade grinders and burr grinders.

Blade grinders (also known as whirly grinders) are your dime-a-dozen grinders that aren’t much different from the blades one sees in a kitchen blender.

Always electric, these grinders consist of one or two blades attached to a motor that ‘grinds’ by whipping around and breaking any beans that get in its way.

While approachable and inexpensive, we don’t recommend using this type of grinder on your beans. The resulting ground coffee will be a bad-tasting motley crew of large chunks and fine powder.

An uneven grind leads to an uneven brew, and you’re going to need a lot of milk to hide the sourness and bitter aftertaste that inevitably comes along with blade-ground coffee.

The much better alternative is the beautiful burr grinder, which not only grounds consistently but will often feature multiple grind size settings! While available in electric models, we prefer old-school manual grinders like the Timemore Chestnut C3 Coffee Grinder.

Generally, manual burr grinders are less expensive than their commercial counterparts. Plus, hand grinding gives you a better appreciation for the effort that goes into making coffee (it’s a labour of love)!

Unlike blades, burrs are two cutting discs with burred edges that work together to grind your coffee. Grind size is determined by how close or far apart the cutting discs are from each other.

Burr grinders mill rather than smash up your coffee beans, with more uniform grounds being the end result.

A quick disclaimer: in an ideal world, there would be a universal measuring system for grind sizes. However, in the coffee world, we make do with terms like ‘fine’, ‘medium’, ‘coarse’, and the occasional modifier (‘very fine’, ‘coarser’...the list goes on.).

The same goes for grinder manufacturers. While most grinders will list the grind sizes of their products numerically, there’s no universal standard for these numbers either.

Therefore, we’ve tried our best to give relative examples below, keeping in mind that one should take all this guidance with a grain of salt (or in other words, medium grind)!

Allow yourself room to experiment, using this guide and those set out by your grinder’s manufacturer to perfect how you grind beans at home.

Cold Brew = Very Coarse Grind (likely the coarsest setting on your grinder). Ideal for coffee that brews over hours.

Cupping, Percolators, and French Press = Coarse Grind (similar in size to sea salt flakes). Ideal for coffee brewing methods where the grounds tend to strew long after the initial extraction.

Aeropress, Drip Coffee and Moka Pots = Medium Grind (similar in size to table salt).

Espresso = Fine Grind (similar in size to sand on a beach).

Turkish Coffee or Instant Coffee = Very Fine Grind (likely the finest setting on your grinder). This one is the tiniest step away from powder and is preferred for time-saving brews (think the coffee in steeped bags and pods) or brewing Turkish coffee.

Grind dark roasts coarser than light roasts: that’s right, even the type of coffee your brewing can influence grind size! Dark roast coffee is alway more fragile than light roasts as being in the roaster for longer strips the bean more of compounds and proteins. For that reason, you should err on the side of caution by grinding dark roasts coarser than light roasts.

Grind high-altitude coffees finer than low-grown coffees: high-grown varieties like geisha have fine notes and aromas that translate better in a fine ground. Grind too coarse and you risk missing the more nuanced flavour compounds.

Keep your grinder clean: if your usually-stunning burr grinder starts producing chunky pieces, or the ensuing cup doesn’t taste quite right, it’s usually a sign that you haven’t cleaned it in a while. A mini-vacuum and wipe with a paper towel in between grinds should do the trick.

Grind just before your brew: to ensure freshness and the best flavour possible in the resulting cup. Science tells us that the breakdown of the bean’s cellular walls from grinding speeds up the degradation (read: stale) process. That also means only grinding what you need to make your next cup is always best practice.