Exact Chemex Ratios for Every Chemex Size

Have you ever tried brewing a cup of coffee with a Chemex, and it just tasted off? It may have been too weak or too bitter, and overrode all other subtle flavors. 

There might be a simple solution: maybe, you got the coffee-to-water ratio wrong.

But no worries, we’ll fix it with this article. From determining what kind of ratio you should shoot for to adjusting for different serving sizes – I’ve got you covered.

So grab your Chemex, and let’s dive into one of the fundamentals for a perfect cup of coffee.

Determining the Ideal Chemex Coffee-to-Water Ratio

There are many recommendations when it comes to the Chemex ratio. Most of them lie between 1:12 and 1:17.

Even Chemex recommends putting “one rounded tablespoon of ground coffee for every 5 oz. cup.” This is approximately a 1:10 ratio, but that’s too strong for my standards. In contrast, the Specialty Coffee Association (SCA) recommends 1:18 for pour over, but I find it just a tad watery for my taste.

So what is the best coffee-water ratio for Chemex?

I tend to go with a Chemex ratio of 1:16 – 1:17. This is actually the “magic ratio”, and I think it works great for the Chemex as well. But of course, feel free to adjust based on your personal preferences if you want something with a little more kick.

There are several Chemex sizes, but using this coffee to water ratio makes your job simple. Whatever size your Chemex, always use 1 part coffee with 16 part water. Multiply it up, and you are golden.

Finding that perfect ratio isn’t only because it affects the flavor profile. It impacts the extraction results as well. Take note of the following:

• A lower ratio translates into a stronger and more concentrated brew.
• A higher ratio results in a weaker and lighter brew.

It’s not just the amount of coffee or water. Other factors such as grind size, water temperature, and pour technique all play a role in achieving that perfect balance.

Since we all have our preferences, determining the ratio perfect for you will take some time and experimentation. Remember, there’s no right or wrong answer, but you will need patience to determine what ratio works best for you.

Adjusting Chemex Coffee-to-Water Ratios for Different Serving/Cup Sizes

IMAGE – Different Chemex sizes displayed in a row

Our starting point for calculating the exact coffee and water weight for each serving size will be the “golden ratio”, with 60g of ground coffee to 1000g of water. We’ll adjust it for each size of the Chemex coffee maker based on this ratio.

Note: The water values were calculated by rounding the coffee weight to the nearest 5 or 10-digit mark and then applying the “magic” coffee-to-water ratio of 1:16.67. These ratios provide a good starting point to guide you in your Chemex brewing journey, but they are simply guidelines and aren’t fixed rules.

What’s the coffee-to-water ratio for a Chemex 3-cup (pint-sized) model?

Note: This is for all 3-cup models in the Classic, Glass Handle, and Handblown Series.

• Capacity: 16 oz (473ml)
• 30g of coffee to 500g of water

What’s the coffee-to-water ratio for a Chemex 5-cup model?

Note: This is for the 5-cup model in the Handblown Series.

• Capacity: 25 oz (739ml)
• 45g of coffee to 750g of water

What’s the coffee-to-water ratio for a Chemex 6-cup model?

Note: This is for all 6-cup models in the Classic and Glass Handle Series.

• Capacity: 30 oz (887ml)
• 55g of coffee to 917g of water

What’s the coffee-to-water ratio for a Chemex 8-cup model?

Note: This is for all 8-cup models in the Classic, Glass Handle, and Handblown Series.

• Capacity: 40 oz (1183ml)
• 70g of coffee to 1167g of water

What’s the coffee-to-water ratio for a Chemex 10-cup model?

Note: This is for all 10-cup models in the Classic, Glass Handle, and Handblown Series.

• Capacity: 50 oz (1479ml)
• 90g of coffee to 1500g of water

What’s the coffee-to-water ratio for a Chemex 13-cup model?

Note: This is for the 13-cup model in the Handblown Series.

• Capacity: 65 oz (1922ml)
• 115g of coffee to 1917g of water

Troubleshooting Common Issues with Chemex Coffee Ratios

• If your coffee tastes weaker, remove water or add more coffee grounds and see if that solves the problem.
• When the brew tastes too strong, it’s better to cut back on the coffee beans or dose up the amount of water.
• Maybe your brew is always inconsistent, so pay attention to your technique. Think of a slow and steady pour.
• If your cup tastes too bitter, you’re probably over-extracting it, so adjust your grind size and brew time.
• Stay away from tap water for coffee unless it’s filtered.

Conclusion

The Chemex coffee-to-water ratio may be just one element in brewing, but it is vital to achieving a well-balanced, consistent, and flavorful cup.

It’s best to start with my recommended ratios and adjust from there. Pay attention to the different serving sizes and their specific ratio adjustments to always get the most from your coffee.

Don’t forget to leave a comment below and let me know how these suggestions worked for you.