Grinding Coffee Beans
In this guide we aim to give you the knowledge you need to understand the different methods of grinding and their associated machines. After reading this you’ll have a complete grasp of different coffee grinders and different grinding levels as well as their influence on the quality and taste of coffee.
Because a poor quality grinder can lead to uneven grounds and have a terribly detrimental impact to coffee, coffee grinders are often considered to be one of the most critical pieces of equipment you’ll need to make coffee.
It’s important to note that there are two types of coffee grinders.
The blade grinder, which spins and chips beans into very tiny pieces and the burr grinder, which actually uses a grinding mechanism and generally allows for a more full release of flavor of the beans.
Coffee ground with a burr grinder can sometimes feel more bitter. This is likely attributable to the fact that it leads to a larger volume of coffee beans coming into contact with water at the brewing stage.
Blade grinders tend to be affordable than burr grinders but the applications for coffee ground with this machinery are more limited.
Blade grinders require very close inspection while grinding, as the longer they are used the more fine the grind will end up. Most importantly, because they use blades to chop the coffee beans vs pulverizing them, the grind produced is often uneven and not as fine as those made through pulverization. This means you can’t really use the ground coffee if you want to make espresso or Turkish coffee.
Burr grinders are much more able to produce coffee that is evenly ground and fine enough to be used for any purpose.
These machines can be adjusted in terms of width which makes them adaptable and well suited to espresso, where even grounds are important to ensure coffee isn’t over extracted later on.
Levels or Methods of Grinding
There are different methods and different degrees of grinding coffee beans, and each method or change in how much the coffee beans are ground has a significant impact on the amount of caffeine that will be present in the final product.
A very fine grind will have a larger surface area of coffee that comes into contact with water, and will allow for more caffeine to be extracted.
Different levels of grinding will typically be selected depending on the method of brewing in whichever combination yields the best flavor.
The grind level can often be judged by touch and site and adjustments are often made based on how fast the coffee is ultimately extracted through the espresso machine.
There’s usually an optimal range of time, based on the amount of coffee, the extraction should take. So timing the extraction and applying a process of trial and error can help determine the optimal grind level.
For instance, when grinding espresso, if the coffee is coming out too fast then the grind needs to be finer in order to slow down the extraction.
Conversely if the espresso coffee is coming out too slow it will yield a more sour taste and this usually means the grind needs to be less fine and more coarse.
Part of what determines the optimal grind level and type includes environmental conditions. The temperature and humidity level can cause beans to swell and this too can mean more adjustments are needed in the level of grind to compensate.
This is because the more the beans swell the more tightly packed they get - which reduces the flow rate and leads to over extraction.
It’s actually for this reason that you’ll see most coffee shops recalibrate their grinding machine every morning before they open.
Did You Know?
The Ethiopians actually employ a “coffee ceremony”, where the woman of the household lays our chosen grasses and flowers on the floor, burns incense, and fills a coffee pot with water. The pot is placed over hot coals while green coffee beans are heated in a pan and stirred. The roasted beans will be ground in a wooden bowl. Once the coffee beans are ground they are placed into the heated coffee pot and brought to a boil.
The ceremony consists of serving this coffee in three servings called “abol”, “tona”, and “baraka”, with the third and final serving intended as a blessing to the guests who drink it.
How does grind size affect coffee?
Usually the finer the grind the stronger the coffee. Course grinding can lead to the coffee being under extracted and therefore weaker. Fine grinding promotes solubility and so the extraction is more powerful.
Are used coffee grounds good for anything?
Yes! Coffee grounds, even used, still contain a lot of helpful minerals. They can and are often used in compost, fertilizer, and even skin exfoliation.