Brewing two cups with the Chemex

I sometimes brew coffees for myself and another member of my household. Up until I got my Chemex, I would brew the two coffees separately. I know you can brew two cups of coffee with the Kalita Wave and the V60 but for some reason I have never given it a go. Perhaps I have a subconscious preference for brewing two separate cups because that way I can spend more time brewing coffee.

Before my Chemex arrived, I realised a lot of recipes were tailored to brewing two cups at once. My first brews were all suited for making one cup because I was still experimenting with the device. It turns out my V60 recipe works well on the Chemex and I have not had to do as much experimentation as I did on the V60. But, I wanted to see the Chemex in action brewing two cups. The three-cup Chemex I have is built for making more than one cup.

To start off, I thought I would use my standard recipe with more water. I had to make three changes to my recipe to brew two cups at once. These changes were:

1. Using more bloom water.
2. Using a higher dose of coffee.
3. Using more brew water after the bloom.

I settled on a ratio of 30 grams of coffee to 500 grams of water (the classic 60g/1l dose, recommended by James Hoffmann). I use 15 grams of coffee and 250 grams of water to brew one cup. I knew that my bloom weight would have to be higher than my usual 50 grams. I settled with 100 grams for brewing two cups. I like to bloom with just over three times the amount of coffee I use. 30 grams of coffee * 3 grams of water per ground = 90 grams of water. I added 10 grams to make the number nice and round, leaving me with 100 grams of water to bloom.

This left me with 400 grams to pour after the 30 second bloom phase. I thought I could pour this all at once but this did not turn out to be the case. After the blooming phase, I started to pour my water as slowly as I could. Although my pour was still fast because I find it harder to pour as slow as I can on my V60 with the Chemex. My gooseneck is usually a bit higher in the air because the filter paper is so tall. At a certain point, I realised that I was at risk of nearing the very top of the brewer if I poured any more water. I decided to stop and then I poured in the rest of the water a bit later.

The cup took way over five minutes to brew, reaching the upper bounds of my target brew time. This suggested that the grind size was too fine for the dose. If your coffee takes too long to brew, your grind size needs to be changed. The final cup tasted nice but it had an inherent bitterness that I had not experienced in any of my Chemex cups up until that point. I decided to use a coarser grind, the 22 setting on my Baratza Encore grinder instead of the 20 I use for one cup.

So, I learned two things from my first two-cup brew on the Chemex:

1. Grind coarser for larger doses.
2. Aim for two pours after the bloom.

In my next brew, I poured 100 grams of water for my bloom and I poured another 200 grams of water after the bloom. This left me with 200 grams of water that I still needed to pour into the brew. I poured this in at about 1:30, although I cannot remember the exact time. I may have poured the rest of the water in a bit after this. My guide was the water level. When the water level got lower, I poured in the rest of the water. I still need to make a few more cups for me to write a complete recipe based on my experiences.

The two pours made it easier for me to brew the coffee and gave me a guideline as to how I can brew two cups at once more consistently with the Chemex. The coarser grind helped the water flow a bit quicker, leaving me with a shorter brew time. What about the cup profile? The cup I drank was delicious: the coffee was sweet and the flavours were clear. I now feel a bit more confident brewing with two cups.

The size of the Chemex makes the device great for brewing two cups. Because the decanter is built into the device, I only need to wash one thing when I am done: the Chemex. I do not need to bring out my carafe and wash it in addition to my filter, like I would have to do with the V60 or the Kalita Wave. This is not so much of a concern as the cup profile. I have brewed some delicious cups on the Chemex and I am more than happy to brew more than one if someone else wants to try what I have brewed. I'll definitely be using the Chemex for two-cup brewing going forward.