Coffee Grinds & Percolators: What’s There to Know?

Picture of coffee grinder, percolator, drip setup

Coffee has a fascinating history that, according to many, can be traced back to Ethiopia. While the first coffee beverages were believed to be made from berries, roasting coffee beans became a more accepted method of coffee preparation by the 13th century.

Today, there are several methods that can be used when brewing a hot cup of coffee. Notably, each device that can be used requires a different grind size. Moka pots, for instance, require coffee that has been finely ground, comparable to that of sugar. Drip coffee makers, on the other hand, require a medium-sized grind, or a size consistent with beach sand. Percolators, a more traditional device used to brew excellent-tasting coffee, require a coarse grind similar to sea salt. If the correct grind size is not achieved prior to brewing, the taste will suffer.

Why Does Coffee Need to Be Ground?

To achieve the classic taste many people have associated with coffee, the roasted beans need to be ground. The grinding increases the surface area of the coffee bean, allowing more of it to encounter the hot water. This allows more flavor to be extracted and the aroma to be more powerful.

If whole roasted coffee beans were used to brew a cup of coffee, it would take a long time to extract any flavor. The resulting beverage would be bland, watery, and virtually odorless. The under-extracted result would not resemble the iconic beverage many people know and enjoy today.

Grind Size vs. Taste

There is a proven relationship between the grind size and the quality of the cup of coffee. If the grind size is too big for the device being used, it will under-extract, leaving the flavor flat or comparable to water. If the grind is too fine, it can cause an over-extraction of the coffee and produce a brew that is harsh and unappealing.

Grind Size vs. Caffeine

After researching multiple sources, there’s a clear debate about whether the grind size affects the caffeine level in a cup of coffee. Thanks to a couple of researchers in Orillia, Canada, some interesting data has recently come to light.

After conducting an experiment to find a correlation between grinding time and caffeine content, the scientists discovered that 42 seconds of grinding resulted in a higher caffeine concentration when compared to beans that had been ground for only 10 seconds. With that being said, grinding the beans for more than 42 seconds didn’t result in a larger caffeine concentration. 

Ultimately, they found that beans ground for exactly 42 seconds had more caffeine than those ground for a lesser amount of time. They also concluded that grinding the beans for longer than 42 seconds didn’t affect the caffeine content. Within reason, finer coffee grounds yielded more caffeine in a brewed cup of coffee.

Grind Size vs. Percolators

When brewing coffee with a percolator, the coffee should be ground to a coarse consistency. Since brewing coffee with a percolator can take up to 10 minutes, the coffee is subjected to hot water for a lengthy period of time, especially when compared to other brewing styles.

For this reason, it is necessary to have a larger grind of coffee to avoid over-extraction, which would produce a bitter and distasteful cup of coffee. Using the correct grind size will ultimately produce a robust, flavorful, and aromatic brew.

Pre-Ground vs. Home Ground

While pre-ground coffee can be purchased, grinding your coffee beans at home will ensure they are fresh and at their most flavorful. Sometimes using pre-ground coffee can result in a stale and unfulfilling brew. If you purchase the wrong pre-ground size for the device you are using, it will also impact the quality of the brew.


Grinding beans at home can be easy, especially with the proper tools. Two of the most popular options for this job are burr and blade grinders. The type of appliance you are using to brew coffee should determine which tool you utilize when grinding coffee beans.

Burr Grinders

This tool, which is sometimes referred to as a burr mill, uses two revolving burrs to crush coffee beans. Burr grinders produced ground coffee with an even and consistent ground size, which is important during the brewing process. The two main types of burr grinders include conical burr grinders and flat burr grinders.

Burr grinders are also ideal for achieving a variety of coffee ground sizes, making this tool ideal for those who brew coffee with appliances that require a finer grind or a coarse grind. This tool has settings to help novice coffee grinders achieve just the right grind size they need without feeling overwhelmed by the process.

Blade Grinders

This tool, although considered by some to be less effective, works by chopping up coffee beans with thin blades. Despite its effectiveness at grinding coffee beans, blade grinders do not produce an even or consistent ground. 

This can be problematic and result in over-extraction or under-extraction, especially when brewing with a percolator.

Blade grinders have pre-set sizes to choose from, although there are not as many choices when compared to burr grinders. They are easy to use, however, making them ideal for people who are new to grinding coffee at home.


Grind size is important and should be factored in when brewing coffee. In fact, each appliance requires a different size grind depending on how long the coffee will come in contact with the water. Generally, the longer the coffee grounds encounter the water, the larger the coffee grounds need to be. This ensures the proper amount of flavor and aroma is extracted and the best-tasting cup of coffee is produced.

Percolators require coarse ground coffee, like sea salt, because the coffee is exposed to hot water for 7 to 10 minutes. The best way to ensure the coffee is ground to the right size is to do it at home yourself with a coffee grinder. The best tool for the job, to ensure an even and consistent grind, is the burr grinder. With its different settings and easy usage, you can grind whole coffee beans to just the right consistency to brew a fresh cup of coffee in your percolator.