Want to start a debate among a room full of passionate coffee aficionados? Easy. Ask them what’s the best shape of coffee filter, cone, or flat. Then sit back and let them go at it; you’re almost guaranteed that a heated argument will ensue.
We all know that grind size, the type of coffee you use, and the brewing method you choose ultimately all have an effect on how your filtered coffee tastes.
But does the shape of your coffee filter also have an impact on the flavor of your final brew?
This question has been an ongoing debate between coffee geeks for a long time. In this article, I hope to shed some light on the key differences between the cone versus flat coffee filter, the type of flavor profiles you can expect, and if one filter outperforms another.
Does Coffee Filter Shape Matter, And Why?
Why do some coffee machines require a flat bottomed filter while others call for cone-shaped filters?
If we’re talking about an automatic coffee maker, the different filter designs are typically chosen to work well with the spray head installed in the coffee brewer.
The combination of the type of spray head and a specific filter shape will ensure that the hot water is evenly disappeared over the bed of coffee grounds.
The shape of the filter will then determine just how quickly the water will pass through the coffee grounds.
For example. If the hot water passes through the ground coffee quickly, the brewed coffee will taste weak. Whereas if the water flows through too slowly, the coffee will start to become more bitter.
However, if we’re talking about manual pour-over coffee brewing, the flow rate of the water can be tweaked and fine-tuned by adjusting the grind size of your coffee. How that water flows through is then determined by the shape of the filter.
Cone Filter Or Flat Filter What’s The Difference?
Apart from how they can affect the flow of water, the shape of the filter can also have a noticeable effect on the taste of your coffee, and science can back it up.
The Specialty Coffee Association (SCA) delved a little deeper into the cone or flat coffee filter debate to see if they could solve this conundrum once and for all.
Their testing discovered that inexperienced coffee tasters could distinguish different coffees brewed using different filter shapes.
“In terms of our sensory evaluation, basket filter shape made maybe even a more pronounced impact than the grind size.”
– William Ristenpart, director of the UC Davis Coffee Center
During the research, the only other variable the tasters could distinguish apart from the shape of the filter was the roast level of the coffee.
This clearly proves that the shape of the coffee filter can change the taste profile of the brewed coffee.
But why does the filter shape make such a big difference? Simply put, it’s all to do with how the water flows through either the cone or flat filter, which then determines how the coffee is then extracted.
Measuring Extraction Using Both Types Of Coffee Filter
This is where it can get a bit technical.
Measuring the varying extraction results using a cone or flat shaped filter can be gauged using a measurement known as Total Dissolved Solids, or TDS for short.
The measurement essentially tells you the actual amount of coffee in your coffee. A higher TDS indicates that the coffee is more extracted.
So how does this relate to a flat or cone-shaped filter? Here’s where it gets interesting. Using the TDS measurement, flat filters have been found to produce brewed coffee with lower TDS versus a cone filter.
This is with all other brewing variables being equal such as the water temperature, coffee grind size, and pouring technique.
Does A Coffee Filter Affect The Flavor Of Your Brew?
So putting all of the technical jargon to one side, how does the filter shape (cone or flat) affect the flavor of your coffee?
If we’re talking about the flavor profile of your brewed coffee, lower total dissolved solids found in coffee brewed in a flat filter tend to produce sweeter notes like honey, fruits, cereal, and florals.
On the other hand, cone filters typically produce higher levels of total dissolved solids and bring out the darker and earthier flavors found inside the coffee, such as smokey woody flavors, umami notes, dried fruits, winey, salty, and cocoa.
Let’s not forget that the shape of your filter plays a small role in how your final brewed coffee will taste.
But, one of the most significant factors is the type of whole bean coffee you buy, how fresh those beans are, the origin, and how they have been roasted will all play a prominent role in the brewed coffee.
What about Coffee Filter Baskets?
Throughout this article, I have been referencing the shape of the actual filter, but what about the filter basket?
The basket’s shape will determine the shape of the paper filter you’ll use in it.
A cone-shaped conical basket will require a cone paper filter, and the same goes for a square-shaped basket. All the other variables and differences highlighted in this article apply to both the basket’s shape and the filter. They go hand in hand.
If you’ve got this far, you will know that there is no wrong or right type of coffee filter. It doesn’t matter if you brew coffee using a cone or flat kind of filter. One does not make better-tasting coffee compared to the other.
However, the studies and blind taste tests do prove that there is a difference.
If you enjoy a more earthy style of coffee, choosing a conical-shaped basket filter might be a good choice. Those who prefer fruity sweet flavors found in coffee would enjoy the flavor notes a flat filter tends to produce.