Coffee Filter Sizes: Figure Out The Best One For Your Coffee

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Finding suitable coffee filter sizes is a vital step in making high-quality coffee. Yet, few people know how to choose an appropriate one among the sea of filter sizes on the market.

The shapes, materials, four different sizes, and others may confuse you picking a filter size. Thankfully, you can refer to this article, for it explains each factor’s details, helping choose the correct one for your coffee. 

Types of Coffee Filters

Before choosing a size, the most basic knowledge is understanding the coffee filter types you will need. By determining the type you want, it will be easier to find the appropriate size.

Recently, there are two main types: paper (or disposable) and permanent. Type classification is based on the materials it has, affecting the size you will choose.

Permanent Filters

Metal

Manufacturers will use steel to make a metal filter to resist the rust from water impact. Using the metal one means that you can reuse it every time you brew.

However, this type always goes with the specific brewers, so you may not use it for others. The metal size is also unchangeable. It requires using only one fixed size, which matches the settings of a coffee maker or brewer. 

Cloth

Another type of permanent filter is cloth, typically made of organic linen fabric. This material is safe for the user’s health and can be reused many times.

There is no fixed-size cloth filter, so you can use it flexibly for brewing coffee manually. However, it is incompatible with any machine for the different systems.

The advantage of cloth type is to catch the ground with high efficiency (even fine ground). But, it does not absorb the coffee’s oils quickly; consequently, the quality is not as good as using other filters.

Besides, thorough care is necessary if you use cloth type. It is because the fabric is easy to get damaged during use. The hot water and the absorption of chemicals from the used ground can reduce its durability. When you complete using it, clean it instantly and keep it dry for the next brewing.

Paper Filters

Manufacturers have produced the paper filters in two ways: bleached and unbleached.

The process to make a bleached filter has used oxygen or chlorine. Luckily, most manufacturers have made oxygen bleached paper filters, safer for the user’s health.

Contrarily, an unbleached is produced with a natural process, which is more favorable for your health.

It is easy to distinguish each type. The bleached paper always has white color, while the unbleached is brown (light yellow). Their color is also what keeps continuing a debate of which contributes the best in filtering.

When choosing the paper type, you should also consider its thickness, which affects your coffee quality. 

The advisable thickness for light-roasted coffee should be around 0.28 mm. The light-roasted ground is lightweight, hard-to-dissolve, and requires a longer time of brewing. So, with 0.28 mm, the paper type will withstand an extended time. 

On the other hand, a thinner paper is ideal for medium- and dark-roasted coffee. These grounds are fine and easy to extract, so the brewing time is shorter. 

Universal Sizes

This table provides you with universal coffee filter sizes; based on them, you can figure out if your product has an accurate size or not. 

Filter Size Suitable For
#1  6.67cm H x 7.45cm W Single-serve machines
100 6.8cm H x 7.64 cm W – Melitta 100 porcelain filter

– The Aromaboy 

#2 (or called 1×2) 9.4cm H x 10.2cm W – Any 2-6 cup machines

– Any 1-2 cup pour-over systems

102 (outdated)  10.5cm H x 10.2cm W – Melitta Optima Timer

– 102 Porcelain Filter

#3 Only for the size-3 Hario V60
#4 (or called 1×4)  12.8 cm H x 12.1 cm W Any 8-12 cup pour-overs and machines
#6 14.4cm H x 14.6cm W 10-cup-or-more pour overs and machines
1 Pint (basket filter) – Base diameter: 5.05cm 

– Side height: 6.98cm

1-4 cup machines
2 Pint (basket filter) – Base diameter: 8.25cm

– Side height: 6.0325cm

8-12 cup machines

Sizes For Each Filter Shape

Cone Shape

The conical filter has a cone shape; it resembles a funnel with only one wide-mouth, and the other is closed. There are four standard sizes that you can choose from, and they are suitable for many kinds of electric or non-electric coffee makers.

Size Suitable For
#1 Single-serve electric/non-electric units
#2  2-6 cup electric units

1-2 cup non-electric units

#4 8-12 cup electric/non-electric units 
#6 10+ cup non-electric units

It is quite different compared with the universal coffee filter sizes to choose the correct one. If you happen to pick a larger conical metal filter, pay attention to the moment you pour the water into it, some water will splash out if you pour too fast or if the water flow pours too near its top wall. 

Bucket Shape

Bucket or basket filters are the specific product of paper filters, but their shape is akin to cupcake paper. You can use this shape for two sizes: junior and bigger. The junior size will support only four to six-cup coffee makers, while the bigger ones are usable for six to twelve-cup. 

Besides its coffee filter sizes, you should know that its filtering efficiency is not quite good. The cupcake width makes the extraction uneven, so the quality is not at the highest level. 

Disc Shape

A disc shape is round with a hole in the center. It is small and flat, so it is not as flexible as the conical and bucket filters. Its size is not various because typically, you will use it for only a specific tool, a kind of metal cup with large holes on the bottom. 

This metal tool will have a pile, playing the role of attaching with the disc’s hole. Since the metal tool cannot filter, the disc will cover all the large holes and allow water to flow on them. 

The disc shape is unpopular as these coffee filter shapes are hard to use and require many processes. For example, after brewing, you may find it difficult to pull the disc out. 

The Size Explanation

What Is Coffee Filter’s Pore Size?

The pore size range is from 15 to 100 microns. There is no standard in choosing pore size because it is based on materials, shapes, or specific types. But, most filters have 20 microns to ensure high-quality extraction.  

Still, it should be between the range above; if the size is larger than 100 microns, the filtering efficiency decreases, resulting in low-quality coffee. The metal one will have the largest holes, which easily get particles through. 

#2 And #4 Size Mistake

The most common mistake of the size is between #2 and #4. The change of dimension is not significant, with around 2 – 3 cm. If you put two sizes in the table to compare, you will find it difficult to distinguish them.

When you make this mistake and buy the wrong size, you may wonder if you can use the #2 filter for #4 devices and vice versa. Here is your answer: 

You will find it easy to put a #2 filter to a #4 coffee maker for its smaller size. All you need is to make coffee with extra care when adding the coffee ground. If you keep the same amount of ground, pay attention to water coverage over it. Using the smaller one means you face more risks of overflow. 

If you use the #4 filter in the #2 size unit, you can trim it using scissors. After cutting the leftovers, the #4 will become #2 and easily fit your coffee maker. 

You should also note that this trick is applicable for paper filters. If the wrong product is a metal or cloth filter, the best solution is to return them and receive the right one after. 

1×2, #2, And 102 Mistake

Another common mistake is among the 1×2, #2, and 102 sizes.

As mentioned above, people also call the #2 filter with Meilittas name 1×2. So, both sizes are the same, with 9.4cm H x 10.2cm W. 

Regarding the 102 sizes, the dimension difference is insignificant despite the larger size with 10.5cm H x 10.2cm W. The size difference is only 1.1cm in height, which is hard to distinguish by visual comparison, even if you put both products on the table. 

Because of the only 1.1 cm difference in height, people have used both interchangeably. You will not find any change in the coffee quality of using these sizes. So, if you buy the wrong size between 102 and #2, that product is still usable. 

Which Size Is A Standard Coffee Filter?

The standard size is 2 pints, which fits 8-12 cup devices. It is a basket filter, as you will use in a drip coffee machine. 

This size is standard because manufacturers have focused on producing many 8-12 cup machines on the market. Also, this line is high-demand as it lives up to most consumers’ needs. 

However, the standard size does not mean it matches your preferences. The advice is to determine your machine requirement and choose the suitable type first; then, consider the correct size. 

Substitutes For Coffee Filters

Paper Towel

The paper towel is a temporary substitute if you do not have the right filter. You will need to fold the paper a few times and keep the liner as tall as possible. 

Yet, it is not advisable to use paper towels frequently because of paper bleaching. Normally, manufacturers produce it for wiping, so it may have some chemicals that are not good for your health in the long run.

In fact, paper towels are always bleached by using chlorine. So, when you pour the hot water into it, the chlorine dioxins may flow with the water into your cup. Although the amount of this chemical is not much, filtering this way, in the long run, will primarily cause health risks, such as cancer. 

Toilet Paper

Toilet paper functions the same as a paper towel. You also need to fold it to fit the coffee maker but ensure that the ground is suitable for the paper endurance. When getting wet, the toilet paper is prone to be torn and will ruin all your effort and materials. 

Toilet paper is also harmful to your health for the bleached chemicals. So, you should only refer to it as the last resort. 

Rag

Rag is likely a cloth filter, but you may need to notice its thickness for better efficiency. Use a thick-fabric rag if you want a light-roasted cup and vice versa. 

Also, make sure the rag is old and no longer used because the coffee water will leave stains, hard to remove after filtering. 

Make sure you use a clean rag. The dirty one will have dust and bacteria, which are harmful to your health. 

Sock

You may be surprised by using a sock to filter. Although it sounds disgusting, people have tried this method, and it works.

You should not use the used sock because it is sickening and unhealthy, even if you wash it to the cleanest. So, the better choice is to use a new sock. 

Yet, this substitute has a weakness. Both the old and new ones will have a strange smell, and it may ruin your coffee fragrance. Make sure you wash the new one several times before using it.

There are also many types of socks with different colors and thicknesses. Choosing a suitable thickness will increase the quality of coffee, and you should avoid colorful socks because the color dying is not good for your health.

Cheesecloth

Cheesecloth is often used in the cheese-making process, but you also can use it for coffee. This cloth type is thinner than many casual cloth filters, so you should use it to brew medium- to dark-roasted coffee. 

It is not advisable to use cheesecloth with light-roasted coffee, for it doesn’t guarantee enough brewing time. 

This cloth is also easy to get stains, but it will not affect the filtering quality. After using it, rinse the cheesecloth with water and keep it dry for the next use. 

Reusable Tea Bag

You can use the reusable tea bag for brewing coffee. It is just a bag with a band in the opening. After pouring the water into the bag, you can pull the band to close the mouth. This action helps you keep the heat of water, contributing to a tasteful result. 

Yet, this substitute is a hard-to-clean option. The coffee particles tend to stick tightly on the cloth, so you may need to rinse it several times.

You also need to make sure the tea bag does not have a tea smell before using. If this smell appears in the coffee, a picky person may dislike that cup of joe.  

Kopi Tubruk Method

You can try the Kopi Tubruk method, an Indonesian coffee brewing in case of having no coffee filter. 

Here is the process:

  • Scoop the coffee ground into the cup, and add the sugar amount as you want. 
  • Then, let’s boil the water. The water temperature mustn’t reach the boiling point. Once the water has almost reached its highest temperature, you will pour it into the cup. 
  • Use a spoon or a stick to stir evenly.
  • Let it rest for 3 – 5 minutes. This period is necessary to wait for the ground to slowly fall down the bottom, which allows you to drink without filtering.
  • Enjoy your result! 

Mud Coffee

The mud coffee is the same as the Kopi Tubruk method, but the order is contrary. You will not pour the water into the ground; Instead, you add grounds to hot water. There is also no requirement of water temperature, so you will simply boil it. 

Then, stir evenly and let it rest for 5 minutes. Do another stir and rest again for 1 minute so that the ground can fall to the bottom. Enjoy it after that. 

FAQs

Do Filters Type And Size Affect The Taste?

Yes, the type can affect the taste. The different filters you use, the different tastes you have. For example, using cloth type may filter both the grounds and oils, so the fragrance may not be as good as using a metal one. 

The size also affects the coffee result. If you use a #2 filter, you will use a lower water amount when pouring than a #4 size. If you follow the standard cup when brewing, you may realize that the bigger size you use, the milder taste you have. 

Do Coffee Filters Go Bad After Used?

Yes, they can go bad after use. The permanent filters are reusable many times till their durability runs out. For instance, you may notice your steel filter gets some rust after years of use. Some find that it only takes several months to change another because of the bad preservation conditions. 

A cloth type is easier to go bad after use. The hot water and the absorption of coffee essence can damage the fabric structure. That is why you need extra care for this filter if you want to use it for a long period. 

For any permanent filter, it is necessary to keep it dry after rinsing with water. A cool place is advisable to prevent the fungi growth, which primarily breaks the filter. 

This factor is also what makes people consider using the paper type. It requires no maintenance, and after use, you only need to throw it away. This type is convenient as it saves a lot of time you will take care of the filter. 

Still, it also goes bad if you do not preserve it well. Keep the paper filters in a cool and dry place or follow the preservation instruction. 

Can I Combine The Used Coffee Filter With A New One?

Yes, you can combine the used filter with a new one (paper type applied only). You can also apply it to the coffee ground instead of throwing it after brewing. 

For example, if you use a disc filter, you will place one layer first (including filter and coffee ground). Then, put another layer on it, and continue pouring the water. The second time, you may have coffee with a stronger taste and fragrance. 

You should apply this method instantly after the first brewing. The used coffee ground is easily spoiled so that it can lower the quality of the 2nd coffee-making.

Are Brown Coffee Filters Better Than White?

People realize the difference between bleached and unbleached paper filters is the color. The bleached is white, while the unbleached has a brown hue. 

There is a debate between the two kinds, and people think that brown one will affect coffee quality because of its color. However, it is not the truth. Because of being unbleached, the brown does not come from the color dye; it is a natural color of paper. 

Both bleached and unbleached types make the same coffee quality. The only difference is that brown is more eco-friendly and health-safety than white one. 

Conclusion

Have you understood all about the coffee filter sizes? Based on the useful information above, we hope you can find the right size for a flavorful and aromatic coffee shot. 

It is advisable to understand your coffee makers/machines before finding a coffee filter. Thanks to that, you can get the correct filter matching your preferences. 

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Almost 20 years already spent committed to coffee and more than 3 years of experience as a barista at Starbucks. Madelyn Doyle graduated with a Bachelor’s Degree in Nutritional Science from the University of California and finished the Coffee Skills Program at the Specialty Coffee Association (SCA).