Brewing Guide - The Osmotic Flow

10 Minute Read

What is the best pour-over method?

What’s the difference between the ‘Osmotic Flow’ and ‘Full Immersion technique’?

How to make a perfect bloom for pour-over?

These are the common questions that baristas face when beginning their specialty coffee journey. While there is numerous jargon, understanding these concepts has become essential for baristas. One of the key concepts that all baristas should know is the basics behind the pour-over method. As a strong advocate for the ‘Osmotic Flow’ method, this short blog will briefly explain various concepts that revolve around the ‘Osmotic Flow.’

What’s the pour-over Method? What are the common types of pour-over methods?

The pour-over method is one of the main methods of brewing specialty coffee. Usually done by hand, the pour-over process involves water flow to extract the essence from the ground coffee. While the basic concept is simple, aspects such as the temperature, the strength in the water flow, and even the pouring technique may negatively impact the results. There are two variations within the pour-over method: the ‘Full immersion method’ and the ‘Osmotic Flow.’ 

Full Immersion Method 

The “Full immersion" method is a hand-drip brewing method that does not involve water flow to extract the coffee essence. This method is synonymous with drippers that are significantly filled with water, as shown in the picture above. While it is the most accepted pour-over method, there are several criticisms of the method.

The main criticism for this method is the overall integrity of the coffee that it creates. During the pour-over process, it is common to see a sedimentary layer form after the extraction process. The sedimentary layer is the leftovers of the powder that isn’t extracted during the process. This method is known for creating coffee that contains more sedimentary layers. This outcome is a result of the water removing the entire coffee powder. By completely submerging the coffee powder, the sedimentary layer is also significantly extracted. 

Osmotic Flow

The “Osmotic-flow" is the pour-over method advocated by Cafec. The technique is unique in its ability to provide better extraction of the coffee powder. The process extracts the coffee by continuously pouring it into a centralised point. The Osmotic flow utilises the water flow passing through the filtering layer. When the flow generates a difference in concentration between coffee essence and water, and the pleasant taste of coffee is brought out fully into coffee liquid by osmotic pressure. The first indicator of good osmotic pressure is blooming.

‘Blooming’

“Blooming” is the outcome of successfully conducting the osmotic flow. When pouring hot water into the coffee powder, the gases contained within the powder will be released and pushed out. This results in the formation of a bubble in the center of the coffee powder. By allowing the gas to expand the coffee powder fully, the water flows in the spaces instead of the gas. Continuous pouring through the filtering layer at the center after the blooming process allows the coffee powder osmotic flow to extract the coffee. The Osmotic flow enables the extraction of the coffee to be centralised, which helps maintain the integrity of the coffee. 

How to do a proper 'Osmotic Flow'?

After learning the concepts revolving around the osmotic flow, here’s a short guide to help put it all together.

1. Place the ground coffee on the proper measurement into the dripper that contains filter paper.
2. Begin the osmotic process by tipping a dripper to make 90°angle between water and the surface of coffee grounds and pouring into a single point in the center of the coffee powder.
3. When successfully conducted, ‘Blooming’ will occur and can be seen by a bubble appearing.
4. After the ‘Bloom’ deflates, begin drawing a small circle while pouring into the center of the coffee powder. Repeat this process until all the allocated amount of water is used.
5. When successfully done, the result will be a dripper that still has a significant sedimentary layer (Leftover coffee powder).

Just like any kind of love, a love for specialty coffee can only grow through nurturing. One of the many methods of increasing this passion is better understanding the techniques that will give the best results. The “Osmotic Flow’ is the pour-over method advocated by Cafec. We highly regard this method due to its effectiveness and the quality of results. By understanding the basic concepts behind making a proper ‘Osmotic Flow,’ we hope this guide may help further develop your passion for specialty coffee.