AeroPress: Paper or Metal Filters?

When it comes to coffee, people become extremely involved with minutiae. Or at least it might seem that way from the outside, but to us, the small things matter. Stacking each important detail on top of one another until we achieve our very own coffee pyramid is how great coffee is made!"

And one of these small yet very important things is which filter you choose for your AeroPress. The AeroPress needs specific filters because they must be a perfect fit or else we risk leakage of coffee grounds. Fortunately, there are many AeroPress-specific filters out there to choose from. But is that a good thing? With so many options to choose from, we might feel a little overwhelmed. How to know which filters are good and which are bad?

In general, there are two types of filters, each having their own pros and cons. These are paper filters, usually good for one or two coffee and disposable, and reusable metal filters which can last months working just as well as they did the first time.

Let’s check them out in more detail.

Paper filters

Paper filters are largely favored when it comes to anything but espresso machines. Even AeroPress themselves have stated that while they consider paper filters to be less than ideal because of the amount of waste they generate, they “…recommend using paper filters as they always perform better in taste tests”¹.

There are two types of paper filters:

White filters.

White paper filters are, basically, bleached filters. Although some other chemicals may play a part in the bleaching depending on the manufacturer, the main ingredient here is bleach. Bleach, as we know, has a very particular smell and taste. Even if rinsed, white paper filters still risk having a certain taste quality that isn’t present with metal filters and if not rinsed can mess with the taste of your coffee.

The most common way of bleaching paper is by using chlorine. The paper is first cleaned with hot water baths, then soaked in chlorine until it becomes white enough. This method, though cheap and easier for manufacturers, is the one that leaves the most trace. (i.e. Chlorine odor).

Another popular way of bleaching paper is by oxygen bleaching. If you’ve ever bought a cleaning product that starts with “Oxy”, you have used this type of bleach. It tends to be more expensive, therefore oxygen-bleached paper filters will be pricier, but it is better for the environment. And although there is a general notion that these types of filters don’t have the unpleasant taste that bleached filters do, it all comes down to personal preferences.

Brown filters

Brown paper filters are generally the same as white paper filters. Because they have not been bleached, the scent and taste left by this chemical are instead replaced by the scent and taste of -you guessed it- paper. Now, as much as tasting paper is preferable to tasting bleach, the flavor of paper has a more prevalent taste than that of bleach. The problem with brown paper filters is that, no matter how much you rinse them, the taste doesn’t seem to ever completely go away.

Therefore, while they are a better choice for the environment, when it comes to flavor they are indeed inferior to bleached paper filters. The taste might be pleasant for some and even complimentary to certain drinks, but in general it isn’t desirable.

Metal filters

Metal filters' whole selling point is that you can use the same one over and over again. Unlike paper filters, you don’t have to dispose of them after one use, which is why they are considered much more “eco-friendly”.

The difference, however, is that paper filters are much more effective at filtering. Metal filters consisting of just one layer -like the type that can be used with the AeroPress- are much more prone to allowing those pesky loose coffee grounds find their way into your coffee cup. That affects taste, it affects aroma, and it makes your coffee look cloudy. In fact, paper filters trap a lot of the oils found in coffee beans— metal filters are much less effective at this, letting through most of these natural oils.

Although some studies have shown that a certain type of oil found in these fine coffee particles can raise your cholesterol, the amount you would be consuming by using metal filters is so small that it wouldn’t have an impact on your health unless you’re drinking ten or more cups of espresso a day.

Convenience

Another thing we must consider is convenience because, after taste, we prefer that which is convenient.

Metal filters are more convenient than paper filters when it comes to buying. For a metal filter, you buy one, you’re set for months. But with paper filters, it becomes sort of a weekly chore: You have to remind yourself to check every now and then to see whether you’re low on stock, and if you are, you have to either order online or go to the store and buy– it’s quite a hassle.

Paper filters are more convenient when it’s time to clean up because you don’t really have to clean up at all. Paper filters are disposed of, and that’s the end of it. Metal filters have to be cared for. You must not let your metal filter be in contact with coffee grounds for too long or they’ll get stained. Additionally, if you don’t clean them right away they’ll always have a strong coffee smell… It can be bothersome owning a metal filter.