Note: I wrote this article a few days ago, before more extensive experiments with the device.
Earlier today, I got a feeling that I should brew a coffee with the Aeropress. I enjoy using the Aeropress but I have not used the device since I purchased my Kalita Wave. I have enjoyed the ritual of learning to use the Kalita Wave and the brewing device produces an exceptional cup profile. When I first got the Wave, I spent a lot of time playing around with brewing variables such as agitation and pouring technique. I have settled down a little bit now that I have made a few good brews on the device. I wanted to revisit the Aeropress because I have made so many great coffees with the device and it had been a while.
My first impression was that I had forgotten some of my recipe. I have only been using the Kalita Wave for a week or two and yet I had to spend a minute or two thinking about how I brewed coffee with the Aeropress. This made me think that I may as well experiment rather than stick to the same rules I had been following for a while. Using the Kalita Wave has been an experiment in itself, learning how to use a new brewing device. I may have made dozens of, if not over a hundred, brews on the Aeropress, but I thought to myself that there is always room to experiment with brewing coffee.
I almost winged this brew to see what would happen. I used the 15 setting on my Encore grinder, which I have been using for my Wave brewing for the last day or two. I could not definitively remember the Aeropress setting so I thought I would leave the grinder where it was. This time, I brewed without a bloom phase, opting to pour in the water fully. This may have been what caused me to forget to agitate 30 seconds into the brew when I normally do. Because I agitate just before I pour the rest of the water into the coffee after the bloom, I had no trigger to remind myself to stir.
I cannot remember exactly when I agitated but it was later in the brew. This led to an interesting observation. Stirring breaks the crust in an Aeropress brew. This is not something I have thought a lot about. My old recipe called for a 30 second bloom where the brewing chamber was only filled half-way with water. A full crust like you may see in a French press never formed; the real crust was smaller. I think this is down to how I would stir immediately after the bloom, thus breaking the crust before it could grow any larger.
I poured the water for this brew using my new gooseneck kettle, which arrived as soon as I got my Kalita Wave. Thus, I had not used the gooseneck kettle on my Aeropress to-date. I am glad I did not buy a gooseneck early in my home brewing journey because it had very little impact on the brew. The water did flow more steadily, like you would expect with a gooseneck, but my goal was just to saturate the grounds rather than use a particular pour. This is just like brewing with a French press. The goal is to saturate the grounds and as long as the grounds are saturated your pouring technique is not as important (of course, I suspect people will have their own opinions on how to pour water into an immersion device, but this is my opinion).
The cup profile for my Aeropress was different to that of the Kalita Wave. I may brew two coffees side-by-side to take more detailed notes on what differences exist between the cup profiles of the two brewing methods. I did note that one cup tasted a bit more acidic than I got from my Kalita Wave but this was not a side-by-side comparison. Suffice to say that brewing device does have an impact on how coffee tastes.
I have read due to the different ways in which water comes in contact with the coffee between the Aeropress and the Kalita Wave. Whereas the Kalita Wave is constantly saturated with new water, the Aeropress spends time in contact with the same water with the duration of the brew cycle. This affects what compounds are extracted because fresh water is more efficient at extracting compounds. But, this is only what I have read.
My Aeropress brew was cloudier than any I have made on my Kalita Wave thus far. This is an observation I have made with many of my Aeropress brews in the past but it is something I have ignored. My mug is black which affects my ability to see the true colour of the coffee. But, all the brews that I have made with the Kalita Wave so far made me question why this is. In my short search for an answer, I happened upon an interesting posts on the CoffeeGeek forum (archived).
Apparently Aeropress filters, which at the time of the 2012 post I read were made from standard filter papers, lose some of their structural integrity when wet. This not a problem in and of itself. But, the forces these filters undergo during the brewing process cause them to clog more easily. This makes them less efficient at keeping the fines, or little coffee particles, out of a brew.
This is not an issue in regular drip coffee because the filters are not exposed to the same level of pressure as they are in an Aeropress.
I have not done extensive reading into this topic and so I am open to alternate theories. This one sounds reasonable but there is probably more to it than I have read.
This one brew in the morning kicked off a lot of observations and I brewed another cup shortly after with my Aeropress. Overall, I was reminded of how flexible this brewing device is. I forgot some of my recipe and used a different grind size but the resulting coffees were still delicious and sweet. I experimented a little bit. I love the experimental nature of brewing coffee.