How To Use An Aeropress: An Advanced Guide

Well if you have read many of our articles you will know that here at The Coffee Folk we love the Aeropress. We love using it, we love experimenting with it, we love the coffee it produces. It has gradually become what is probably our favourite coffee maker. 

If you don’t already own an Aeropress then the best piece of advice that I can give you is check out our review of the Aeropress here and go and buy one! It may well be the best coffee investment you make in 2020!

This article is really directed at those who own an Aeropress and now want to know how to use it. So whether you are relatively new to the world of the Aeropress or are a seasoned veteran, we are sure you will find something helpful in this article. 

The Aim of this Article

The flexibility of the Aeropress is both its greatest attraction as well as its greatest hurdle to using it correctly. Because there are so many ways you can use it, there are also so many ways that you can stuff it up. In our earlier article we wrote and still believe that with the Aeropress it is remarkably easy to get good results, but takes far more effort than is sometimes thought to get great results. 

So instead of giving you one foolproof recipe, we have opted in this article to give you three different ways to make an Aeropress, all of which come with a good track record. And then for the bulk of the rest of the article we will really drill down into understanding how changing different brewing parameters affects the final flavour. 

The reason for this is that in our own experience of using the Aeropress, especially if you are switching between different beans, you often have the feeling that the taste is just slightly off. Maybe slightly too bitter, maybe slightly sour, maybe just slightly off in a way that is hard to pin down. And you know that something needs to be tweaked but it is hard to know what to do, do you change grind settings if you own a grinder? Do you change the water temperature? Coffee to water ratio? Brew time? There are that many things you can change that it can be somewhat overwhelming. In this article we will try and help you understand how changing any of these affects the taste of the brew. 

How to Use an Aeropress: Three Alternatives

Equipment you will Need

Option One: The Inverted Method

The inverted method has got a lot of hype in the Aeropress world almost since day dot. The biggest advantages of this method is that it means that it means that there will be no leakage during extraction (which happens to a smaller or greater degree with the traditional method). In addition, it is just somewhat satisfying executing that flip flawlessly!

Option Two: The Traditional Method

Despite some misgivings regarding drip leakage during extraction, the traditional method is still often used for Aeropress even on the world scene. The following method is the one used by Shuichi Sasaki when he won the 2014 Aeropress World Championship in 2014 in Italy. This is the method we use daily and have found it to provide some of the most consistent results across a range of beans. 

Option Three: The Bypassing Method

The final major way to make Aeropress is effectively to brew a small strong amount of coffee and then add additional water after brewing. This is called bypassing and has been commonly used by winners of the World Aeropress Championship. The advantage of this way of using the Aeropress is that it often brings out different flavours of the beans than the methods above. The following recipe is the 2016 Aeropress World Championship winning recipe from Filip Kucharcyzk of Poland. 

Understanding the Taste of Coffee

Instinctively from the very first sip we usually know if a coffee is good. It tastes complex, you can get at least an idea of the distinctives of the beans, and it is just plain enjoyable to drink. And similarly, usually by the first sip we can taste if something is off. It tastes overly bitter, perhaps strangely dry or salty, and anywhere on the spectrum from slightly off to plain unpalatable. 

So we know something isn’t quite what it could be, but we often don’t know why or struggle to find the words to explain what we are sensing. In this section we will unpack the theory of why coffee tastes as it does, before getting into knowing what to change.

The taste of coffee ultimately comes down to something called extraction. If you know a bit about coffee then no doubt you have heard this term tossed around. Basically coffee beans are soluble which means that just like sugar particles they dissolve if they come into contact with water, and the hotter the water is the faster the beans dissolve. And the taste of coffee is the direct result of how much or how little of the beans dissolve.

Technically speaking, a coffee bean is 30% soluble and 70% insoluble compounds. The taste that we experience in that first sip is how much of the 30% soluble part has been extracted. The general rule of thumb in the specialty coffee industry is that the ideal extraction extracts 18-22% of the coffee bean.

So when we use the words over-extracted and under-extracted we are really referring to how much of the coffee bean has been ‘extracted’ or dissolved out of the soluble part of the coffee bean and into the cup. The reason that this affects the taste is that different flavours of the beans are extracted at different points in the extraction process.

So first the fruity and acidic notes are extracted, then the sweetness, and finally the more bitter notes. So in terms of flavour notes first come the fruity and bright notes, then the sweeter ones such as nuts, caramel, chocolate, and finally the heavier notes such as ash, malt, tobacco. 

So if your brew tastes overly acidic then it probably hasn’t been extracted enough. Similarly if it is bitter and ashy then you have extracted too much of the coffee beans.

So if that is under and over-extracted then what is the sweet spot? It is here that the insights of Australian coffee trainer Matt Perger are super helpful. As Matt explains, the taste of a brew gets sweeter and sweeter as you move from under-extracted towards over-extracted. The sweet spot is to stop extracting right before the sweetness transitions into sourness. 

The aim of the game here is to extract the coffee up to a point just before you get unpalatable dryness or bitterness. It’s the sweetest spot. Guaranteed. Every time

Matt Perger

So optimal sweetness is the goal, whether in Aeropress or actually any other brewing method. And the way to get there is by either extracting more or less from the coffee beans by changing the brewing parameters. 

In each of the following brewing parameters, changing them can either lead to more extraction or less extraction. You change your brewing parameters based on taste, as a way to get closer to that optimal sweetness. 

Understanding Brewing Parameters

So finally we get to the brewing parameters. And the term ‘brewing parameters’ is really just a fancy way of saying the different aspects of the Aeropress brewing process that you can change. 

So below are the different things that you can tweak or alter in your coffee brewing with the Aeropress that will affect the flavour and extraction. It is important that you only change one brewing parameter at a time as that will enable you to tell if it is helping or hindering. And remember the goal of experimenting with these is to get closer to the ideal extraction.

The following chart summarizes how each of these brewing parameters affects extraction.

Grind Size

Changing grind size is the single most effective way to counter either over or under-extraction. This means that while it is absolutely possible to brew Aeropress without a burr grinder, it will never get as good results. The reason that this so affects the brew is that your grind particle size determines how much surface area of the beans comes into contact with the water. 

With a finer grind there is more surface area exposed and so the flavours will extract quicker. Similarly, the more coarse your grind, the less surface area is exposed and so the beans will extract more slowly. And so if your Aeropress coffee is tasting bitter or dry then one of the first steps to try is a slightly coarser grind setting. Likewise, if it tastes sour then changing the grind setting one setting finer speeds up the extraction.

In terms of what this practically looks like, it is a good idea to look up online what the recommended grind settings for your grinder are for different brewing methods. These will provide a good starting point from which you can experiment. From there you can tweak the grind size one setting or click at a time. Especially when you switch beans it is often a good idea to at least try tweaking the grind size and see how it affects the flavour.

The other aspect that does come into finding the ideal grind size is the beans themselves; the roast level, the altitude in which they were grown, and the age of the beans. Usually it is best to use a slightly more coarse setting for dark roasts and a finer one for light roasts. Similarly it is usually recommended that you use a finer grind setting for coffees that have been grown at a higher altitude. Older beans can also be livened up a little by adjusting the grind size to a finer setting. To understand more about how grind size and particle consistency affects extraction see our article here.

So the first brewing parameter to try changing is grind size. If the coffee tastes bitter or dry then go to a coarser grind setting, and if it tastes sour then change to a finer setting.

Brew Time

The next aspect that you can change is brew time. Because the Aeropress is an immersion method, the length of contact time between the grinds and the water directly impacts the flavour of the coffee. The rule to keep in mind with brew time is the longer you brew, the more you extract. 

So if you want to extract less from the beans then opt for a shorter brew time, and if you are looking to extract more then lengthen the brew time. This brewing parameter is also highly connected to the previous one. So if your grind size is already very fine then you will want to keep your brew time fairly short as it will easily over-extract, and the same principle applies for a coarser grind.

Another aspect of brew or steeping time is plunge time or how long you take to press down the Aeropress. Often newbies to the world of Aeropress tend to plunge quickly and with maximum pressure. But while this feels satisfying it often actually hinders even extraction. When you apply too much pressure to the plunger you create channelling where the majority of the water passes through only one part of the grinds and so over extracts that part and under-extracts the rest. It is the principle that the water (like electricity) will always choose the path of least resistance.

So it is far better to opt for a slower plunger time of at least 30 seconds. This avoids channeling and makes for a more consistent and even extraction. This has been well attested in the World Aeropress Championships where long plunge times are common. Aim to put gentle pressure on the plunger and then almost let the plunge go down on its own accord. 

So the longer the brew time, the more it extracts.

Water Temperature

Another variable that plays into the extraction and final taste of the Aeropress coffee is water temperature. The rule of thumb here is that the hotter the water, the more you extract. It is similar to the way that if you think about how sugar dissolves in water, and the hotter the water is, the quicker it dissolves. The same principle applies to coffee grinds, higher water temperature translates to faster extraction rates because many of the compounds that make up coffee beans are more soluble at higher temperatures.

According to the Specialty Coffee Association of America the Gold Cup Standard for brewing coffee requires a water temperature of between 195 and 205F (or 91-96C). However, when it comes to Aeropress, many methods and recipes tend to favour a lower brewing temperature. So for example if you look at the various recipes of the winners of the World Aeropress Championships, many of them use water temperatures anywhere between 170 and 185F (77-85C). 

So in terms of tweaking this, if you are using a dark roast it is often helpful to opt for a lower water temperature to avoid over-extraction and reduce the risk of bitter flavours. Similarly, if your roast is particularly light, it can be helpful to go for a higher temperature to speed up extraction. 

So when changing water temperature go hotter for more or faster extraction, and cooler for less or slower extraction. 

Water to Coffee Ratio

The final brewing parameter that you can tweak is the water to coffee ratio. We have placed this last as we would recommend trying altering the other parameters first. The reason being that different methods have very specific water and coffee ratios that have usually been chosen for a good reason. So while you can play with this, it should not be the first thing that you change.

Most Aeropress methods will use somewhere in the range of 14-18g of coffee to 250g of water (remember 1g of water =1ml). So if you are looking to increase the intensity or strength of the coffee you can either increase the beans used or decrease the water used. And similarly, if you are looking to decrease the strength/intensity you can either decrease the beans used or increase the water used. 

So if your coffee is tasting bitter and dry and over-extracted then you could either decrease the beans used (which will decrease surface area) or you can increase the water used. Similarly, if it tastes sour and acidic you can speed up  extraction by using more beans or using less water. Again, this should probably be the last brewing parameter that you choose to change. 

A helpful way to think about using these brewing parameters is the following chart:

So the point of the diagram is that the easiest way to get to the ideal extraction is to over extract and then gradually extract less (by tweaking the brewing parameters) until it is no longer bitter and harsh but not yet sour and acidic. The sweet point is just before the sweetness turns into bitterness.

Other Aspects of Brewing with the Aeropress

So those are the different brewing parameters that you can change with Aeropress and now we will just briefly touch on a few other aspects that can play into the taste of the coffee.

The Filters Used

One of the important choices to make around Aeropresses is which type of filter to opt for. The Aeropress will typically come with 350 paper filters but there are also metal filters that you can purchase as well as more carefully produced paper filters. Basically paper filters make for a cleaner cup of coffee with more clarity, while metal filters allow more of the coffee oils and grit to make it into the cup and so add body.

One fairly common hack that is often used, and that we do virtually all the time, is to use two of the regular paper filters instead of one. This makes for a super clean cup and will particularly appeal to those who are used to or enjoy pour over coffee.

Another type of paper filter that is making waves is the AESIR paper filters. While these are fairly pricey they are excellent quality and are far more thick than usual Aeropress filters which makes for an exceptionally clean and bright cup. For a comprehensive guide to aeropress filters check out our article here.

The Stir

Another thing that you often come across with different Aeropress methods is some form of stir. Basically what stirring achieves is agitation. By moving the grinds around you help avoid channeling and make sure that the water is extracting evenly from all the grinds. It is the same principle behind pouring in concentric circles when brewing pour over. Basically the more the agitation or stirring, the quicker and more even the extraction. 

Turbulence caused by agitation always accelerates extraction and usually improves the uniformity of extraction

Scott Rao

One interesting thing that has come up in the World Aeropress Championship a number times is a longer period of vigorous stirring often with chopsticks. So while the stirrer that comes with the Aeropress is more than sufficient, if you do have a pair of chopsticks at home, you could try using them. If nothing else it is rather enjoyable!

The Hiss

I am sure that you have noticed that when plunging the Aeropress you can hear the hiss of air releasing as you come to the end of your press. Again this can affect the flavour in the cup. By pushing down as far as you can to the end of the hiss you will get more oils and a more full-bodied cup similar to French Press. 

For this reason many users stop pressing as soon as they hear the start of the hiss. This makes for a more clean cup with less of the bitter notes that come through the final press. So again, it depends on what you prefer, but our preference is to stop at the start of the hiss. 

The Bloom 

Another thing that two of our three methods utilize is a ‘bloom’ period. This is the time when a small amount of water is poured over the coffee grinds and then left for usually 25-45 seconds. This is a step that in many ways originates with Pour Over and has been exported to Aeropress. Basically the rationale behind this is that the bloom allows Carbon Dioxide that resides in the beans to release which makes for a more even extraction. So especially if your beans are fresh you will often be able to see bubbles of gas coming to the top of the grind bed and an almost blossoming appearance. 

While the exact science of this is disputed, the idea is that it helps make for more consistent extraction, and it is just quite satisfying to watch.  

The Takeaway

We hope this article has been informative in helping you both to have a few different Aeropress methods to play with, and knowing how changing the brewing parameters affects the final cup. 

Using the Aeropress is a journey with plenty of ups and downs, which can both produce superb coffee and disappointing coffee. Our encouragement to you, is keep experimenting, keep trying different beans, different methods, and find what tastes the best for you. Brewing Coffee is ultimately subjective, the end goal is a cup of coffee that you enjoy! So find what works for you.