Size matters when it come to your coffee grounds. Unfortunately, many a great coffee has been let down by incorrect grind size and perfecting this variable will help you to improve the taste of your coffee. Unexpected and undesirable flavours such as sour, bitter or burnt tasting brews are nobody's friend so read on and discover how to achieve an ideal, controlled extraction. In short - a darn good brew!
Having the best coffee maker and beans won’t mean anything if you don’t understand extraction which is explored in more detail here if you are up for a more in-depth journey. In short, the purpose of grinding coffee beans is to increase the surface area coming into contact with water. The greater the surface area, the more water that can pass over the coffee and more extraction of the soluble particles from the beans can occur.
The basic idea...
- Extraction rate increases with a larger surface area, ie, finer grounds.
- The higher the extraction rate, the less contact time is needed between the coffee and water (shorter extraction).
- A coarser grind has less surface area, coffee will take a longer to extract.
The plunger (French Press) suits a coarser grind, as the extraction time is longer than that of an espresso shot. The pressure and shorter extraction time of an espresso machine will require a finer grind. Pour over devices need medium-fine grinds. If you are an Aeropress fan, there is a degree of flexibility, so you can experiment with different variables and recipes to create an ideal cup.
What does poorly extracted coffee taste like?
Under extraction Sour, acidic, sometimes salty and lacking sweetness. This happens when the water isn’t able to pull out enough from the grounds.
Over extraction Bitter, astringent notes (think unsweetened black tea), tasteless, muted notes. Dry, ashy, astringent, or strong/intense flavours suggest over-extraction. These flavours occur when water draws too much material out of coffee.
A stumbling block for the beginner home barista is the typical chart on grind size. What does a fine or medium fine grind look like? How coarse is coarse? In order to make these terms easier to understand, we've made a chart that uses pantry staples or items found around the home as a comparison.
We hope this helps to shed light on grind sizes and in turn lead to better-tasting coffee at home.
Need a grinder for home? Check out our Hario hand grinder here.
To download the chart at a larger size, click here