Using a Chemex For The Perfect Pourover

Temperatures are starting to drop in the Denver area, and WE. ARE. HERE. FOR. IT!

I am starting to find myself reaching for the Chemex more and more over my standard morning Cold Brew.  This month we have an Ethiopian Natural from Elm Coffee Roasters out of Seattle that is perfect for these cooler mornings.

This Coffee is bright, clean, and fruit forward as you would expect with an Ethiopian Natural.  Notes of peach, champagne, and lavender have the folks at Elm touting this as the “most exceptional coffees they’ve ever had”.

Before I end up going on a tangent about how much I enjoy this offering, let’s get back to why we are here – 

Brewing The With Your Chemex

Jump to the good stuff

First, make sure you have the following handy-

Why Chemex?

If you are like me, and find yourself reaching for a roast with bright, clean, acidic notes – Chemex brewing is for you.  The all glass construction ensures that you don’t end up with any “off” flavors, and what you are tasting is 100% coffee.

The filters used by a Chemex are thicker than what you would see with a typical drip maker, coupled with the unique conical shape this results in longer extraction times.  This means that the total time for water to pass through the coffee is longer than your standard countertop electric brewer.  The end result is a clean cup of coffee, with little to no sediment and a flavor profile that is more developed.  If you are looking for the tasting notes displayed on the front of the coffee bag, the Chemex is a perfect way for you to discover those.

As implied above, the filter does a great job of filtering out sediment and oils from the coffee.  So if you are a coffee drinker that usually prefers a more full-bodied cup (similar to a french press), you may find that Chemex brewing is not for you.

Water Temperature

Ideally, you want your water in the 195-205 degrees Fahrenheit range. If your water is too hot, you will end up with a bitter cup of coffee. Some electric kettles have the ability to dial in your temperature to the exact degree. 

If you do not have an electric kettle (or even a thermometer) that is completely fine!  I usually let the water come to a boil, and then just take it off the heat and let it sit for 30 seconds or so. 

Grinding Your Coffee

There are many different opinions on what is the perfect ratio for Chemex pour overs.  Some say 15:1 while others are adamant that 17:1 will yield the best cup.  Personally I find myself changing it up depending on the flavor profile of the roast and what I am craving at the time.  If I am looking for a lighter cup I go 17:1 or 18:1, for heavier cups I stick to 15:1.  My advice would just be to start with 15:1 and adjust from there.  This means that you will need 15 parts water for every 1 part coffee (15g water for every 1g of ground coffee).

The grind size can yield very different cups as well.  Too coarse, and you will find your pour overs are coming out too bitter due to over extraction.  Too fine, and the water will flow through the grounds quickly leaving you with an under extracted cup.  Ideally you want your coffee to be medium coarse grind, with the grounds between the size of table salt and kosher salt.

Prepping Your Filter

Before you start brewing, you will need to make sure you have prepped your filter.  This step is super simple, you just need to place the filter in the top part of your Chemex and rinse the filter with hot water.  After the filter is rinsed, pour out the excess water that has dripped into the bottom part of your Chemex.

This will do 2 things.  First, the filter will now stick to the sides of the Chemex preventing the filter from slipping into the bottom while brewing.  Secondly this will keep flavors from the paper from mixing into your finished pour over.

Allow the Grounds to Bloom

The filter has been saturated, excess water has been dumped out, now it is time to load the grounds into the filter. First pour is intended to wet the grounds and allow them to “bloom”.  Essentially we want to pour twice the amount of hot water as there are grounds, and allow the water to absorb for 30-45 seconds – it is that simple.

I usually brew enough coffee for 2 large (12oz) cups, and find that I use 40-45 grams of ground coffee for this.  So for the blooming process, I will wet the grounds with 80-90 grams of hot water (195-205 degrees Fahrenheit).  You will notice that during this period the coffee starts to expand.  This is due to CO2 escaping from the beans, allowing for the next pour of hot water to be fully absorbed by the coffee and eliminating a sour taste that could usually be imparted by excess CO2. 

Pour Over Technique

 After blooming your grounds, you are ready for the final step of Chemex brewing.

In 200g increments, slowly pour the water in a circular motion.  You do not want to pour directly on the sides of the filter, as you want to make sure the water makes contact with your grounds instead of just flowing down the sides and into the pot. 

You may also notice that grounds are sticking to the side of the filter in a conical shape.  This is sometimes referred to as “high & dry” grounds.  Ideally you want to make sure that you end up with a flat bed of grounds after brewing is finished.  I will typically start my next increment with a wide sweeping circular motion to ensure that I cover the entire surface, and grounds do not stick to the sides.

TL;DR – How to Use A Chemex

  1. Heat your water to a temperature of 195-205 degrees Fahrenheit
  2. While water is heating, grind your coffee.  You will want to have 1 gram of coffee for every 15-18 grams of water.  For 2 large 12 oz cups, I start with 40g ground coffee and ~700g of water
  3. Place your filter in the Chemex and rinse with hot water, draining excess
  4. Load grounds into filter
  5. Wet grounds with hot water and allow them to bloom for 30-45 seconds.  If using 40g of coffee, add 80g of water for blooming process
  6. After blooming, begin pouring hot water in circular motion in 200g increments until you have reached your ratio of 15:1-18:1
  7. Discard filter and grounds, pour freshly brewed coffee into cup and enjoy!

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