If you've ever made coffee using a filter, you might have noticed the little ridges along the side of the filter. But have you ever wondered what they're actually for? While they might seem like a simple design choice, these subtle pleats play a crucial role—and they directly influence the taste of your coffee.
The Science Behind Coffee Filter Ridges
The ridges—also known as folds or pleats—are there to allow air to circulate between the filter and the wall of the filter holder. Without those ridges, as soon as hot water hits the coffee grounds, the smooth paper filter would be pulled tightly against the sides of the holder. This could slow down or even block the flow of water, leading to over-extraction: bitter, too-strong coffee with an unpleasant aftertaste.
By creating space between the filter and the holder, the ridges ensure that water can flow smoothly and evenly through the coffee grounds. The result? A better extraction process and a more balanced, fuller flavor.
Additional Benefits of Ridged Filters
There's another benefit too: the ridges reinforce the filter paper, making it sturdier during brewing and less likely to tear—especially important if you're making pour-over coffee by hand (like with a V60 or Chemex).
Those ridges create just enough space for air to escape and for water to flow evenly. As a result, you get a more consistent extraction of all the flavorful compounds in your ground coffee. This is the secret to achieving a balanced and flavorful cup—one that brings out the coffee's delicate notes without introducing astringency or bitterness.
Engineering Excellence in Your Morning Cup
It's easy to overlook such a minor design detail, but next time you slot a ridged filter into your coffee maker or fold one open for your morning ritual, remember: those pleats are making your coffee better, cup after cup. Every delicious, aromatic sip is thanks, in part, to clever and thoughtful engineering.
So, next time you fold your coffee filter or place it in the holder, remember: those ridges are there for a good reason. They help you brew better coffee, cup after cup.