“The coffee grind” is always a subject for debate, criticism and critique for baristas and coffee enthusiasts everywhere. A coffee grind is impacted by seemingly everything - humidity, ambient room temperature, roast degree and even bean density.
Part of the fun of making coffee is tinkering with the grinder and analysing the shift in flavour. So whether you're a seasoned professional or just dedicated caffeine lover, we've compiled a few talking points to catapult you into “the know”.
There are two main types of grinders you may have encountered.
We have the blade grinder. With its tendency to smash coffee beans into inconsistent sized pieces, it may be a better option than pre-ground coffee but in reality its probably better used to make fruit smoothies.
The Burr grinder is the running favourite. Made up of two close fitting rings, with angled teeth that grind together to create a uniformly ground bean, ready for extraction. The burr grinders can be both electrical or manual and they're always adjustable. The ways and amounts of adjustments that can be made are usually reflected on their rung in the ladder of “superiority”.
THE GRIND SIZE
Of course there is always room for there to be some larger and smaller pieces in your grind, coffee is brittle and can break off in a non-uniform way. That being said, having a broad range of grind particles can be disastrous because the finer particles will over extract and the larger articles will be left under-extracted.
The finer your grind is, the higher the surface area of the coffee will be. If the surface area is greater, the coffee extraction will be slower because the water has better access to the flavourful compounds that coffee holds.
Two of the most common DIY coffee methods have quite different grind needs;
A percolator is designed to let gravity do the work. The water flows through the bed of coffee, so the surface area needs to be relatively high. During this process the water has a limited contact period with the coffee. It washes through and extracts the flavour as it goes.
Grind is important here because having a coarser grind would mean that the water would flow quicker through the bed of coffee and risk under-extraction.
Plunger / French Press
The grind for a French Press is little bit fool proof as long as you're in the ballpark. This is because the fineness of the grind only affects the rate of extraction, since the water-coffee contact period is determined by the person pushing the plunger.
GRIND CHEAT SHEET
1 - Turkish
The finest coffee your grinder can produce without clogging up
2 - Fine Espresso
A very fine grind, probably with some clumping
3 - Espresso
A fine grind, perhaps with some clumping, particularly when moulded into an espresso portafilter
4 - Fine filter
Somewhere between a filter grind and espresso
5 - Filter
Coffee grounds have a caster/superfine sugar texture rather than a finer powder of espresso
6 - Coarse Filter
Immersion brewing territory, as coarse as large sea salt flakes
7 - Very coarse
Similar to the size of rock salt pieces, this grind is only used for long immersion brews
8 - Chunks
Large pieces of coffee shrapnel. Too big for normal brewing