Why does grind size matter?

If you’ve ever wondered why your coffee tastes too bitter, too weak, or just not quite right, chances are the grind size has something to do with it. Using the right grind size for your chosen brewing method is essentially to produce a great tasting, balanced cup of coffee. 

The size of the ground coffee affects the speed at which water passes through it and therefore how much flavour it extracts. Too fine a grind, and the water struggles to pass through, leading to over-extraction and bitter, harsh flavours. Too coarse, and the water flows too quickly, leading to under-extraction and weak, sour flavours.

Whole Bean

Best For: Bean-to-Cup Machine

Many coffee machines are designed to use Whole Beans, instead of pre-ground coffee. They grind the perfect amount of coffee, right before brewing, to ensure its freshness and maximum flavour.

Medium Grind

Best For: Cafetière / Pour Over / Clever Dripper

Resembles: Sand or coarse table salt

A medium grind is the most versatile grinding option, as it is used in a number of brewing methods. It strikes the right balance between being coarse enough for water to flow freely, but fine enough to extract good flavour and body from the coffee.

• Cafetière / French Press: This method involves immersing medium ground coffee in hot water for several minutes, before pressing down on the plunger to filter the coffee. As it steeps, the water extracts the natural oils and flavours of the coffee. Medium ground coffee works best, as too fine a grind may slip through the filter - resulting in a gritty end result.
  

• Pour Over / V60: This method uses gravity to extract the coffee, as hot water is poured over the grounds before passing through a paper or metal filter. A medium grind prevents the filter from getting clogged and the coffee from tasting too weak.
  

• Clever Dripper: The Clever Dripper combines gravity and immersion brewing, in one convenient gadget. A medium grind ensures a full-bodied yet smooth brew.

Medium-Fine Grind

Best For: AeroPress

Resembles: Caster sugar

The AeroPress is a versatile brewing method, with the option to brew anything from short, espresso-style serves to a long, black coffee.  We recommend starting with a medium-fine grind as it allows for quick extraction under pressure without clogging the filter.

• AeroPress: This method uses both immersion and pressure to extract flavour from the coffee grounds. As it takes 1-2 minutes to brew, a medium-fine grind helps draw out enough flavour in a short amount of time.

Fine Grind

Best For: Espresso Machine or Moka Pot

Resembles: Table salt

A fine grind is essential for pressure-based brewing methods, like an Espresso Machine or Moka Pot. These methods involve hot water being forced through tightly packed grounds, in a short amount of time. A fine grind exposes more of the coffee’s surface area, making it easier for the water to quickly extract its full flavour.

• Espresso Machine: Hot water is forced through the coffee in 25–30 seconds. A fine grind ensures the water slows down enough to extract the full flavour and oils of the coffee, creating the rich crema and strong taste espresso is known for.
• Moka Pot: The Moka Pot uses the same principles as an Espresso Machine, but with stovetop pressure. Too coarse a grind will lead to thin, weak coffee, but too fine can clog the filter.

How to find the right grind size?

Taste Test: The easiest way to tell if your grind size isn't right is from the taste of the coffee you're brewing. If your coffee tastes weak or sour, your grind size is too large or too coarse. If your coffee is bitter, harsh or burnt tasting, your grind size is to small or too fine.

Brewing Time: A good indication of what grind size is best for a brewing method, is its brew time. Longer brew times (like that of a Cafetière) need coarser or larger grind sizes, whilst shorter brew times (like that of an Espresso Machine) need finer or smaller grind sizes.

Consistency: An even and consistent grind size is important in producing a great tasting cup of coffee. This can be achieved by using a grinder specifically designed for coffee grinding.