Brewing a delicious pot of coffee includes a few different considerations other than filling your coffee maker with pre-ground coffee in the morning.
Most people are content with this routine, whether they lack the knowledge or prefer the convenience of putting in the filter, grinds and hitting the power button.
The problem here if you really care about the taste of your coffee is that grind size is the most important factor in relation to the method or device you use to brew your coffee. A small change in grind size can have a significant effect on the taste of your coffee.
The Brew Process
During the coffee brewing process, extraction of the compounds into the brew occurs. When speaking about extraction specifically, how many compounds extracted from the grinds into your brew is the most important factor.
What comes into play here as a formula for success is coffee ratio, brew time, water temperature and yes, grind size. These factors in the formula vary depending on your brew method – are you using a chemex? A Turkish pot? Or are you using the pour over method.
Course Grind vs. Fine Grind
A coarse grind has larger, loose particles that allows water flow to be fairly rapid. Since you have larger particles and faster flowing water, there is less time and surface area for the water to make contact. This results in less extraction time leading to less compounds in your brew.
A finer grind is more compact so this means more surface area for the water to touch and provides less space for the water to flow through, slowing down the movement throughout the grinds and increasing the extraction or brew time.
Depending on your method of brewing if you don’t use the required grind size, you may have:
- Under-extracted coffee results in a sour acidic taste.
- Over-extracted coffee results in a dull flavour that tastes bitter.
Keeping in mind that coffee to water ratio, water temperature and brew time are factors towards a delicious cup of coffee depending on your brew method, if you have larger coffee grinds for a device that requires finer grinds, your brew time will be faster resulting in under-extracted acidic tasting coffee.
An example is an immersion brewer, such as an Aeropress that requires the grounds to be immersed in water for a few minutes. The contact time of water within the grinds should be longer so a more finer grind should be used – slowing down the flow of water through the ground coffee beans.
- Larger surface area (short extraction time)
- Small, compact surface area (longer extraction time)
- Extra Course
- Medium Grind
- Medium-Fine Grind
- Fine Grind
- Extra-Fine Grind