There are two main types of coffee brewers: drip and immersion. They each make coffee slightly different, but one of them is far more efficient. Here’s why!
Back when our friends over at Barista Hustle sent out samples of coffee from their subscription service, there was a fair amount of anxiety on how to get the most out of each small bag. So, the BH team started thinking through various home brew methods to maximize efficiency on sample coffee.
That discussion prompted this video on the great debate of drip versus immersion. Specifically, looking at efficiency between the two brew methods.
So why is drip better? The difference between the two stems from how and when your coffee and water interact. Drip is on the left here and comes in many forms: pour-over drippers like Stagg [X] and [XF], Chemex, batch brewer, etc. When fresh water is constantly flowing through grinds and exits through the brewer into the cup, it’s considered drip.
Immersion is on the right and also comes in a few forms: French press, cupping bowls, siphon, our Duo Coffee Steeper, etc. Pretty much any method where coffee and water are mingling together until the end of the brew process.
Now why is this difference important? Let’s say we want to make a 200 gram brew with both methods and both cups need to have 1.5% strength (TDS) and 20% extraction for optimal flavor. We start with 15 grams of coffee in the dripper and add 230 grams of water. We make the pour-over and water flows for 2 minutes, picking up grams of soluble coffee as it goes. 200 grams of brew is deposited in the cup.
Here’s the important part: 30 grams of water is left behind because the grounds soak up twice their weight in water (this may change depending on the type of coffee and roast). We get to 1.5% strength (TDS) and 20% extraction.
Doing the same with immersion, we add 15 grams of coffee and 230 grams of water. We end up with 200 grams of coffee but 1.08% strength (TDS) and 20% extraction.
The difference in strength/TDS between drip and immersion points to the efficiency of the two methods. With drip, the water extracts coffee and then exits the dripper. As you progress through your brew, the water in and around the grounds becomes more dilute until it approaches 0% strength. Think of the color of coffee exiting a pour-over at the end of an extraction. It’s a lot lighter than at the start of your brew. That super diluted coffee is what ends up in and around the grounds.
With immersion, the extraction process is homogeneous within the vessel. The water around the grinds continues to get stronger and stronger and ends up the same strength as your final brew, regardless if it’s in your cup or in your brew vessel. That extra brew can’t just come from nowhere; it has to come from somewhere. Hence, why the TDS of the immersion coffee was lower.
So what do we have to do to make both brews identical strength/TDS? We need to add more coffee to the immersion method. To get the same result, we must add 15% more coffee to immersion as well as more water (234.4 grams) to account for the new dry coffee soaking up more water.
Now that’s not a lot, but if we do some math, it really adds up. To make a 200 gram cup of drip coffee, you need 15 grams of ground coffee and if you are using an immersion brewer you need 17.2 grams. If you’re making a cup every day for a year and we assumed the coffee costs $23/kilo you’ll save $9,235 using a dripper. This gets even more dramatic when we're talking cafe volumes. Long story short, you need to use about 15% more coffee when brewing with immersion, which means drip wins in an efficiency comparison.
To check out the original Barista Hustle blog post on drip versus immersion, click here!