Infusion method is one huge category of coffee brewing. In contrast to permeation method like paper drip, coffee grounds are infused in water to get extraction out. There are numerous brewing method using infusion. I will quickly go over four distinctive infusion brewings.
The coolest thing about siphon is how it’s visually entertaining. It’s like a science project you did back in elementary school and or middle school. From coffee brewing perspective, siphon is pretty unique as well.
It has two separate compartment, one on the bottom, the other on top. each is connected with a path where water and vapor can go through. First boil the water on the bottom compartment, and the pressure increases due to vaporization of water. The pressure pushes water up to the top compartment where grounds are waiting. Usually you stir the a little bit to let the coffee contact the water evenly. After a couple minutes of infusion, the vapor liquifies in the bottom compartment by cooling it down. That drops the internal pressure and the coffee from top compartment is sucked into the bottom through the filtered path.
As I said earlier, it’s really cool to look at. Besides its look, siphon is good at maintaining steady cup quality at each brewing. The water temperature and pulling pressure at the filtration is almost always the same. The problem is the water temperature is close to boiling point and is considered to be too high. You could argue that it’s hard to avoid extracting unwanted bitterness and other unpleasant taste.
French press has many fans and is my favorite infusion method too. Just remember a few things like not too fine grinding, water temperature(generally 195°F to 205°F), right infusion time(3 to 4 minutes), and slow plunging. Once you find your favorite setting, as long as you follow it, you get the perfect cup each time with very little effort. Because of the easiness and quality, french press is as popular as paper drip. The major difference is that coffee from french press tends to have less clarity due to small coffee particles, but it has richness which comes from coffee oil which the paper dripper usually filters out.
This method might be rather classified as permeation brewing than infusion brewing. Percolator was invented in France and got its popularity in the US during American Frontier era. The coffee you see in western movie is probably brewed with this method. Tt’s still available at places, but drip coffee machine has taken over its position since a half century ago. It almost feels like invented only for camping nowadays.
The percolator has a top and bottom compartments. Water is boiled on the bottom and the pressure pushes up to the top where coffee grounds are. The coffee water is filtered through tiny holes and go back down to the bottom compartment. The water is constantly going through coffee grounds and gradually becoming darker. When it gets dark enough it’s ready.
I don’t know how one could make a good cup of coffee out of percolator. The coffee exposed to boiling water for quite some time is naturally overly extracted.
This is the most primitive way of brewing. It is the method used for cupping: just pouring water into cup with ground coffee and drink the top clear layer. You could say this is unplunged French press coffee. There is no reason for us to do this. In a situation where you have hot water and ground coffee, you usually have access to some brewing equipment. So this shouldn’t be your choice of brewing. However, the trendy product Cafe Solo may be categorized here. I could see how this product could reintroduce this segment of brewing to general consumers.