Head Barista Tsubasa will share his wisdom with us today in regards to the two extraction methods that can be done using the Hario Immersion Dripper Switch.
Checkout our YouTube video:
Immersion Method vs. Filter Method
1. Immersion method: immersing the coffee grounds in water to brings out the coffee flavors.
2. Filter method: pouring hot water over the coffee bed and letting the water drip down.
The two methods creates different flavors and outcomes. There are several factors that effect the end result, but today we will be exploring the 'osmotic pressure'.
Osmotic pressure and coffee extraction
Coffee beans contain much essence and are high in density, while water on the other hand are have low density. If you bring these two substances with different density level together, osmotic pressure will occur.
Water will seep into the coffee through its porous membrane, decreasing its density. By repeating this process of osmosis, the coffee essence is extracted as the water flows through the coffee grounds.
Immersion method: the coffee essence is extracted rapidly at the beginning and gradually eases overtime.
Pour-over method (hybrid): you constantly keep adding water, which in turn, maintains the osmotic pressure in the coffee bed throughout the extraction.
Which is why you might find that coffee tasting stronger even after making the grind size coarser. Coarser grind increases the flow rate and water drips down quickly. Which increases the osmotic pressure causing the flavors to be extracted easily.
We hope that we clearly explain the correlation of coffee extraction and osmotic pressure. Please keep this concept in mind as you experiment with your Switch dripper.