Like all things coffee, what is originally thought to be quite simple (whether that’s roasting, grinding, or brewing), is quite complex and has a tremendous impact on the entire process of making a great cup of coffee. The simple (or is it?) coffee filter can be included in this category.
When you say "coffee filter," most people picture a paper coffee filter. But to the trained eye, what appears to be just a coffee filter is actually a bleached, bucket filter that’s primarily used for average coffeemakers.
Between the different coffee filter sizes, shapes, and materials, it can be overwhelming to understand how these subtle differences impact your daily cup of coffee. But fret not, our article will help you guide you along and learn to understand the differences and how these differences can impact the overall coffee brewing experience.
Coffee Filter Shapes
Generally speaking, there are three main “shapes” of coffee filters: conical filters, bucket filters, and disc filters. Most people are familiar with the commercialized conical and bucket filters. These filters are used most often for home and commercial coffee brewers, so let's start with these and then get into the differences between them all.
As you probably guessed based on the name, conical coffee filters form a cone shape, starting with a wide opening that gradually tapers to a fine point. These types of coffee filters are used from home drip coffeemakers and pour-over coffee systems.
Conical filters come in four standard sizes based upon the volume that your coffee maker produces.
Coffee Filter Sizes
- #1 Coffee Filters: This size is suited for one cup coffeemakers or pour-over systems
- #2 Coffee Filters: This size is used for two-to-six cup coffeemakers/one-to-two cup pour overs
- #4 Coffee Filters: This size is made for eight-to-ten cup coffeemakers or pour-over systems
- #6 Coffee Filters: The size is used for large, ten+ cup coffeemakers
Bucket coffee filters (sometimes called basket filters) are mainly found in the traditional drip coffeemakers. Unlike its conical cousin, the bucket filter possesses a wide mouth and a wide flat bottom. But its size isn't always beneficial. If the coffee grounds are uneven, the brewed coffee can be under-extracted and bitter.
Disc coffee filters are predominantly used in Aeropress coffee makers or other percolator coffee makers, like the French Press. These types of filters are best used with medium-coarse to medium ground coffee. You can browse our selection of replacement disc filters for the Aeropress if you want to see what they look like or are stocking up for later.
Types of Coffee Filters
Broadly speaking, there are two types of coffee filters: paper (sometimes called disposable) and permanent. The materials that make up the coffee filter are the most important aspect and can truly affect the coffee bean’s flavor qualities during the brewing process.
From under extraction to soaking up coffee’s flavorful oils to environmental concerns, we'll break down all the different aspects you'll need to consider when choosing a coffee filter. See? It's not as simple as one would think.
Permanent filters fall into two distinct categories: metal and reusable. Both are great options for the environmentally friendly coffee connoisseur who wants to cut down on waste while brewing their morning cup of coffee.
Metal filters are made of steel or a similar material. This type of coffee filter has a few pros and cons. While they cut down on paper and produce less waste, they're usually made for pour-overs, limiting their potential uses for other coffee brewers.
Additionally, they are not biodegradable, and if not properly cleaned, small particles and other coffee grime can accumulate and negatively affect your freshly brewed coffee’s taste. Luckily, Coffee Bean Corral offers a wide range of cleaning products to clean away the coffee grime, helping you maintain your metal filter’s shelf life and continue to brew flavor coffee all year round.
The other type of “permanent” coffee filter that can be found is a cloth coffee filter. These types of coffee filters tend to be a bit rare (at least in North America). Usually, cloth filters are made from finely woven fibers that act as a sieve, catching any coffee grounds (even fine grounds) without absorbing the coffee's natural oils too quickly.
James Hoffman's video is a great primer about how to best care for cloth filters - thoroughly washing the cloth filter between every use. Also, be mindful that they should not dry out too much nor remain damp between uses, as this can leave off-flavors.
Generally, these types of filters are reusable up to around 100 brews before the accumulation of micro-grounds, and coffee oils will begin to flavor your coffee.
Paper coffee filters are the most common type of coffee filter due to their affordability and ease of use. They are disposable, yet biodegradable, although they can still produce excess waste if not composted. There are two types of paper filters: bleached and unbleached.
Generally, paper coffee filters are either bleached with oxygen or chlorine. Thankfully, most of today’s coffee filters are oxygen bleached. You can tell if a paper coffee filter is bleached by its white color.
Bleaching allows the paper filter to catch finer particles, leaving you with a smooth tasting cup free of grounds. The trade-off is that the bleached paper filter absorbs the coffee ground's natural oils and leaves you with a weaker tasting cup overall.
Just as the name describes, unbleached coffee filters are just that. Generally, they are not as white as bleached filters. However, because of its lack of processing, the filter imparts a papery taste to your already weakened cup of coffee. You can alleviate the papery taste by running hot water through the filter before using it.
FAQs & Other Concerns
Do Certain Types of Coffee Filters Affect Taste?
Yes. As noted above, different coffee filters can affect the taste of one’s coffee. The importance of this depends on you and your preferred brewing method. By illustrating the differences, we hope to have cleared any confusion about which coffee filter should be used.
Do Coffee Filters “Go Bad”?
Yes and no. Again, this depends on the type of coffee filter you are using. Paper filters will not go bad, but it is not wise to reuse them. Metal filters can be used indefinitely if properly cleaned and cared for. Meanwhile, cloth filters only “go bad” after a certain number of brews.
Can You Compost Your Used Coffee Filter?
Yes, you can compost not only your coffee filter (if it is a paper coffee filter that is) but coffee grounds as well. Coffee filters and coffee grounds make great compost. Rather than throwing them away after brewing, bury your used coffee filter and grounds in your compost.
What Can be Used as a Substitute When I Do Not Have a Coffee Filter?
Lots of things to be frank - toilet paper, muslin cloth, a fine sieve, paper towels, and even cotton socks can be used in a pinch as coffee filters.
However, we do not recommend any of these substitutes, as they are neither designed to be coffee filters and would severely impact the overall quality of the brewed coffee.
As you now see, there is a significant range and variety of coffee filters. From the coffee filter size to the material it is made from, each has its advantages and disadvantages and can affect the result while brewing coffee. We hope that this guide illuminated why those differences matter and how to choose the right filter for the best cup of coffee.