The Best Chemex Ratio (We Tested The Perfect Brew)

Brewing with Chemex is both an art and a science.

Where something as simple as the Chemex ratio (the ratio of water to coffee) can have such a profound impact on the flavor of the drink.

Quick Answer
Chemex recommends you use a tablespoon of grounds for every cup of coffee. This aligns with the SCAA’s recommendation of a brew ratio of between 1:15 and 1:17 or 13 grams of coffee to 200ml of water. For a really strong coffee, a brew ratio of 1:12 may be required. Our recommendation is to start at 1:15 and then tweak it to suit your tastebuds.

Carry on reading to find out more about the Chemex coffee ratio for the perfect brew.

What Is The Golden Coffee Ratio? 

You’ve probably heard that to brew a perfectly balanced cup of coffee, you need to be mindful of the coffee ratio. But what does it all mean?

A coffee ratio, commonly known as a brew ratio, refers to the proportion between coffee and water. Most coffee professionals recommend a ratio of 1:15 and 1:17 because it allows the water to interact with the coffee grounds for even extraction.

How does this translate to the correct weight (by volume) of water and coffee?

Here’s an example using the 1:15 ratio. Let’s say you want to brew 200 ml of coffee.

Take the amount of water and divide it by the consequent: 200/15 = 13g. 

So, for every 200 ml of water, you’ll add 13 g of coffee.

There are several recommended ratios, but these only serve as a guide. When it comes down to it, ratios are personal. Only you can determine the amount of coffee you want to pour into your device. 

Pour Over Vs. Drip Vs. French Press Ratios.

The Speciality Coffee Association (SCA) – an organization that represents coffee professionals all over the world, has a set of ratio “best practices” they suggest coffee enthusiasts adhere to. Depending on the brewing technique you use, they recommend the following to achieve a golden cup of coffee.

Brewing Method	Coffee to Water Ratio
French Press	1:15
Drip	1:18
Pour Over	1:15 to 1:17
Espresso	1:2
Cold Brew	1:4 to 1:8

Pour-over 

For every 400ml (13.5 oz) of water, pour 22 grams of medium-fine grounds.

French press 

36 grams of medium coarse grounds for every 660 ml (22 oz) of water. 

Drip 

For every 50 grams of medium grounds, pour 1 liter (34 oz) of water. 

The Best Chemex Coffee Ratio 

Despite the standardized ratios set out by SCA for pour-over brewing methods, Chemex does have its own proportion that caters to its brewing device. If you’re curious to find out how much coffee to use in your Chemex, the table below summarizes the amount to add for a balanced cup of java. Again, these can be adjusted according to your preference. 

Cup Size	Coffee (mg)	Water (oz/ml)
1 Cup Chemex Coffee Ratio	1 Tbsp (5-7 grams)	5oz (147ml)
2 Cup Chemex Coffee Ratio	2 Tbsp (10-14g)	10oz (294 ml)
3 Cup Chemex Coffee Ratio	3 Tbsp (15-21g)	15oz (441 ml)
4 Cup Chemex Coffee Ratio	4 Tbsp (20-28g)	20oz (588 ml)
6 Cup Chemex Coffee Ratio	6 Tbsp (30-42g)	30oz (882 ml)
8 Cup Chemex Coffee Ratio	8 Tbsp (40-56g)	40oz (1176 ml)

Tips To Easily Measure Out The Right Chemex Coffee Ratio 

When preparing coffee, it’s essential to measure the beans to consistently brew your perfect cup. For that, we recommend the following to ensure you do just that.

• Always weigh your coffee beans. When a recipe calls for 5 grams of grounds, it’s easy to assume it’s the standard teaspoon. But, the volume of the substances you weigh will always differ. Just as 5 grams of sugar weighs differently from 5 grams of sand, coffee grounds will not always weigh the same. Coffee beans come in various roasts. Lighter roasts typically weigh more than dark roasts. This is why you find dark roasts have a few extra beans compared to their light counterpart.
  
  Recommendation: We use these Timemore Coffee Scales which are high precision and USB chargeable.
  
• No Scale? Use a rounded tablespoon. If you don’t have access to a kitchen scale, you can get away with using a spoon, but not just any spoon. According to Chemex, a rounded tablespoon yields the correct amount of grounds required to brew an excellent cup of coffee.

How To Brew The Perfect Chemex Coffee (Step-by-Step)

Now, here’s to the exciting part; brewing the ideal Chemex coffee. Follow the steps below to get started. 

1. Grind your coffee beans to a medium coarse ground (preferably using a burr grinder because it grinds consistently). 
   
2. Open the Chemex filter into a cone shape. One side of the cone should have three layers.
   
3. Place the filter on the brewer. The three-layered part should cover the pouring spout. 
   
4. Put one rounded tablespoon (5-7g) of grounds into the filter. For every 5oz (147 ml) cup, pour one tablespoon of grounds.
   
5. Using a circular motion, pour a small amount of water over the grounds. Wait approximately 30 seconds for the coffee to bloom.
   
6. Slowly pour the remaining water, still using a circular motion. 
   
7. Allow the coffee to brew for approximately 4 minutes.
   
8. Lift the filter and discard.
   
9. Pour and enjoy.

Summary 

Brewing a perfect cup of coffee depends on finding the correct-to-water ratio for your next brew. Though the SCA has a recommended ratio for most brewing techniques, it all comes down to how you prefer your coffee.

Use a ratio of 1:15 as a starting point when brewing with Chemex, then adjust to your taste. That means for a typical two-cup Chemex you’ll need 2 tbsp of ground coffee and 10oz of water.

Once you have a general idea of the best (ratio) practices, and how these apply to Chemex, you can experiment and play around with various roasts and varieties. Doing so ensures you consistently produce a golden cup of java.