Is Aeropress Immersion or Percolation? (Solved & Explained!)

Aeropress is an immersion and not a percolation brew. Aeropress – a special coffee brewing device that is not only long-lasting and simple in terms of its use but offers a number of brewing methods as well. This suggests that coffee is submerged in hot water. It is then filtered out finely with the help of filter paper. 

However, if you are applying pressure and expecting that the resulting beverage will be an espresso, it is not going to happen. This is because you have to apply a pressure of 9 bars for 30 seconds to extract the espresso shot out of your Aeropress. 

Since Aeropress offers full immersion brewing, the resulting beverage is a dense coffee cup that has clarity that is not seen in a French press or any other brewing methods of full immersion.

Other than Aeropress, French press and Syphon are also brewing methods of full immersion, and each device results in a beverage that does not only taste different but also differs in looks as well.

What Is Percolation?

Percolation is a brewing process in which liquid extract the solid particles of coffee

are passed through the beds of grounds. In a brewing process, fresh and clean water is added to the slurry and solids which are packed. Liquid leaves the slurry. This process decreases the concentration of the slurry’s solid throughout the brewing process. 

So it is seen that in the French press the strength of slurry always increases and during percolation the strength of slurry always decreases. This is the most important reason that percolation is much better than immersion as it is a more efficient process of extraction.

If you slowly add the water to the slurry during percolation it makes the TDS very concentrated.

What is the Standard Percolation Extraction Measurement?

When the percolation brewing process is completed the TDS of slurry is extremely low but can also reach zero. That’s why when you are considering the amount of solid extraction during the brewing process of percolation more or less you ignore the number of dissolved solids that remained in slurry.

What Is Immersion?

Immersion is a method that involves the extraction of coffee with water that becomes highly concentrated with the passage of time. Water gradually attains thicker consistency because it sits in with the coffee grounds during the whole brewing process.

Rather than focusing on having a perfectly controlled pour, brewers instead focus on the brew time. With a brewing method such as cupping, coffee grounds are to remain in the water, which allows the drinker to detect the different levels of extraction from the taste.

However, with other immersion methods, coffee grounds will be filtered out completely, such as with certain french presses.

Immersion brewing gives great results for coffee, resulting in a bolder flavor, better color, and more textured body. If coffee drinkers enjoy the taste but don’t particularly like the full-bodied mouthfeel, they can opt for bypassing.

Bypassing is a process of adding extra hot water to a largely concentrated brew, and is actually how an Americano is made.

How Does Immersion Brewing Take Place?

When water comes in contact with the coffee grounds, it leads to a sudden rise in 

the concentration of coffee solids in the sludge. Afterward, the concentration goes on increasing gradually without showing any sharp effect. That is why the speed of extraction slows down rapidly during immersion brewing. This relates to the process of diffusion. 

According to the phenomenon of diffusion, a solvent that is present in a more concentrated form in a chemical compound takes less time to extract than the same compound when dissolved in coffee grounds.

During the immersion brewing process when water is added to the grounds the concentration of solid increases rapidly in the slurry. It keeps increasing but at a low rate. This is how the color of coffee looks much darker from a few seconds to a few minutes.

In immersion coffee brewing, the process gives a rich cup of coffee, and the microfiltration

Through immersion makes your cup of coffee super pure. This immersion brewing process

takes about thirty seconds in an Aeropress.

A smooth cup of coffee is formed by this brewing method with the help of the following tools:

  • A stirrer.

  • Plastic Funnel.

  • Coffee scoop.

  • Microfilter and filter holder.

  • The Aeropress.

What Is The Difference Between Percolation and Immersion?

The main difference that sets immersion and percolation apart is the clarity of coffee water. The coffee extracts through immersion results in the extraction of more concentrated water (this is because, for the whole coffee brew, water sits in/ immersed in with the grounds of coffee). Whereas, water extracted through percolation is clear and not concentrated. 

Since Immersion results in the extraction of a more concentrated brew, the extracting speed decreases significantly in the immersion brew. 

This slowing down of the extraction process comes from the diffusion process of physics.

In immersion brewing, the chemical profile of extracted components strongly correlates with the abundance of all those individual components in the coffee beans.

On the other hand, the chemical profile of compounds extracted through percolation brew is related to their speed of extraction

What Is The Recipe For a Hybrid Percolation-Immersion Brewing In Aeropress?

You will need the following ingredients:

  • A medium to fine-sized grinds of lightly roasted coffee.

  • A paper filter.

The recipe for this hybrid brewing is as follows:

  • Pour 55g of water with no dispersion and agitation. 

  • Let it sit for 30 seconds.

  • Pour 45g of water with high dispersion and low agitation. Brew for 30 seconds.

  • Pour another 140g of water with very high agitation. Quickly stir through it and place the plunger. 

  • Steep for 2 minutes.

Using this brewing method results in a perfect balance of brightness and acidity in your cup of coffee which is not only smooth and really sweet but also results in a brew that does not feel over-extracted. 

This hybrid is a combination of a process that starts with the phase of percolation and ends with a phase of immersion.