Java Beat: How Grind Size Affects Your Coffee
This article originally published in Greater Sturbridge Town & Country Living, November 2020 By Elvis Dyer, Owner/Roaster, Sturbridge Coffee Roasters
One of important elements of brewing an awesome cup of coffee is having a coffee grind that correctly corresponds with your brewing time and method. When you grind the coffee bean, you are exposing all the volatile flavors and aromatics from within in the coffee bean. If you took a coffee bean and dropped it in water, you could get some extraction and if you cut the bean in half, you would increase the extraction rate. Basically, that is what is happening when you grind the coffee bean. And how course or fine you grind it impacts your level of flavor and aromatic extraction.
How coarsely or finely you grind your coffee will also affect how quickly or slowly water passes through your coffee. Too coarse a grind, and water will rush through without taking those all-important flavors with it. Too fine a grind, however, and water will pick up flavors you don’t want.
When you grind your coffee finely, you are raising your surface area, which could potentially lead to over extraction. Combine the grind size with time and you have another important factor. The time that hot water is exposed to the coffee particles must be directly proportional to the exposed surface area, or particle size, of the ground coffee. To stick with our fine grind example, smaller particles release flavors more quickly. Therefore, using a fine grind for espresso makes sense as the brew time is just around twenty seconds. The finer grind allows all the desired flavors to be extracted in a shorter time.
When you grind the beans to a courser grind, these larger particles will release flavor more slowly. Therefore, for a French Press, you use a much coarser grind and therefore have an increased brew time.
The main grind types are:
Extra coarse grounds: similar in size to peppercorns, they are best used for cold brews and are perfect for lengthy submersions in water.
Coarse grounds: similar in size to sea salt, this grind size is ideal for French Press and needs about a four-minute brew time for the perfect extraction.
Medium-coarse grounds: similar in look/feel to sand or kosher salt, this grind size is ideal for pour-overs and require an extraction time of approximately two minutes for a balanced cup.
Medium grounds: this is the grind most people are familiar with as it’s used in drip coffee.
Fine grounds: a good benchmark espresso grind.
Super fine grounds: looks like baby powder and is widely used for only one type of coffee – Turkish coffee
Having a uniform grind is important for your coffee experience. An even consistent grind is of utmost importance when brewing coffee. There are two major grinder options – blade or burr. Blade grinders lead to inconsistent grinds even when pulsating. They typically produce powdered coffee in combination with large particles. The finer particles lead to a bitter muddy cup, whereas the larger will under extract. A burr grinder is made up of two revolving abrasive surfaces (called burrs), in between which the coffee is ground, a few beans at a time. There are flat burr grinders and conical burr grinders, however they both grind your coffee well. Burr grinders are preferred over blade grinders because a burr grinds the beans in a uniform size, giving you more control over the grind than you do with a blade.
No matter what type of coffee or espresso drink you are making, getting the right size and consistent coffee grind are critical first steps, after making sure you have the perfect coffee bean to begin with.