Chemex Ratio: Coffee To Water Ratio - A Chemex Brewing Guide

Wondering how to find the best Chemex ratio of coffee to water? Chemex pour-over coffee makers are known for their flavorful, sediment-free pours, coupled with a streamlined, elegant build, making them adored by coffee purists worldwide. The beauty of Chemex lies in its simplicity, but that also means you have to find the best Chemex coffee ratio all on your own, which isn’t always easy. Don’t worry, though. That’s why we’ve created this Chemex brewing guide, to help you find the best Chemex coffee ratios for your desired brew, so you pour the perfect cup of coffee each and every time.

For starters, it helps to understand exactly how the Chemex process works.


Chemex 10 cup Classic Series Pour-Over Glass Coffeemaker                             
          Buy Chemex 10 Cup                              Buy Chemex Reusable Filter

How does Chemex pour-over coffee work?

Chemex coffee makers, like any pour-over coffee maker, simplify the brewing process down to its core steps. You have coffee grounds, ideally ground with a burr grinder, and you have water (hot or cold). The coffee grounds are placed in a filter in the top portion of the Chemex’s hourglass-shaped carafe, and then the water is poured over the coffee grounds, filtering down into the bottom of the carafe as coffee. Voila! 

This process results in a brew that is clean, clear, and consistent because the water extracts the coffee oils and fragrances on its own time and pressure, without any artificial assistance. It naturally results in a more flavorful brew, with strong aromas. Chemex coffee makers are excellent for connoisseurs looking to bring out the complexities and nuances of lighter roast coffees, in particular.

Wondering how to use a Chemex Coffee Maker? We have a guide for that, too!


So, what is the best Chemex coffee ratio?

Well, your Chemex coffee ratio really depends on the type of coffee you’re trying to brew. More coffee grounds and less water lead to a stronger cup of coffee, and the reverse results in weaker coffee. Factors like grind size and water temperature will always play a role, too. No roast is exactly the same. For starters, however, a 1 to 15 coffee-to-water ratio is a good baseline. 

You might be thinking, “Ok dude, I didn’t come here to solve math problems.” Don’t sweat it, we hear you. What that 1:15 Chemex ratio means is that for every gram of coffee you use, you need to pour around 15 grams of water (0.5 oz) over it. This ends up equaling 1 cup of water poured over every 3 tablespoons of ground coffee. 

You can start out making some brews using this 1:15 ratio, but slowly adjust a variety of factors, one at a time, that will affect the coffee’s extraction, such as grind size and water temperature, until you find the perfect blend. Just like you’re performing a science experiment (remember fifth grade?), be sure to adjust variables individually. If you change your Chemex coffee grind size and the water temperature and your coffee ratio all at once, you won’t know which factor did what. 

For best results we recommend using a good quality grinder, here's our top picks:

1. Baratza Virtuoso+: is a high-end electric grinder that is known for its consistent grind and easy-to-use interface. It offers 40 different grind settings, making it ideal for Chemex brewing. ($$$)


Baratza Virtuoso+ Conical Burr Coffee Grinder with Digital Timer Display


 2. OXO BREW Conical Burr Coffee Grinder: For Chemex brewing, the OXO BREW Conical Burr Coffee Grinder is a superb option, featuring 15 distinct grind settings that enable you to customize the grind size to your preference. Furthermore, it includes a built-in scale that simplifies the task of measuring the precise amount of coffee beans required. ($$)


OXO Brew Conical Burr Coffee Grinder


3. Hario Skerton Pro: If you prefer a manual grinder, the Hario Skerton Pro is a great option. It has ceramic conical burrs that provide a consistent grind and is portable and easy to use. ($)                                                                                   


Hario Skerton Pro



How to adjust your Chemex ratios

First off, you want to watch your brewing time. If your pour is filtering too slowly, then your coffee is ground too finely, and clogging up the filter. Try a coarser grind with your burr grinder to speed up the process. If your coffee is filtering too quickly, likewise, it needs to be ground a little finer. 

Brew time varies depending on the size of your coffee maker and the batch you’re making, but for the 6 cup Chemex, expect a brewing time of around four minutes. Once you’re happy with your brew time, adjust based on taste.

My Coffee is too Bitter or Harsh

This likely is resulting from an over-extracted brew. First, try a coarser grind, and you can also add in water at a faster rate to decrease the brewing time. Be sure to avoid stirring (agitating) the coffee bed, as well.

My Coffee is Too Sour or Thin

This means your brew is under-extracted. Try stirring your coffee bed a couple of times during the process to increase extraction, or add in coffee grounds with a finer grind to slow down the brewing process.


Pouring coffee grinds in to Chemex

Tips for brewing the perfect cup of Chemex coffee

Use a Scale

It might seem obvious, but a high-quality coffee scale can play a big role in helping you find the proper ratio. While you can measure out coffee grounds via standard kitchen tablespoons, the grams to tablespoons conversion isn’t precise. It’s much better to measure your coffee via mass, if possible, using a kitchen scale.

Here's our top picks:

1. Hario V60 Drip Coffee Scale: This is an excellent scale for measuring coffee for Chemex. It has a 0.1g accuracy and a timer built into the scale. The timer is crucial for Chemex brewing, as it helps to ensure that the coffee is brewed for the correct amount of time. ($$)

Hario V60 Drip Coffee Scale

2. The Coffee Gator Coffee Scale: is precise, portable, and reliable tool that's great for use with a Chemex coffee maker. It offers accurate measurement, a built-in timer, and a tare function, making it easy to make a consistently great cup of coffee. ($$)

Coffee Gator Coffee Scale

3. The KitchenTour Coffee Scale is a great tool for Chemex coffee makers because of its precision measurement up to 0.1g, built-in timer, tare function, and versatility for other brewing methods. It's easy to use, even for beginners, and the touch-sensitive buttons and large LCD display make it a user-friendly choice. Great quality for lower budget ($)

KitchenTour Coffee Scale with Timer

Brew Less Coffee

It goes without saying that larger batches tend to leave more room for error. If you’re having trouble, try shrinking your brew size until you find a process that works for you, then building upon that.

Use Filtered Water

Your coffee is only as good as the water you use to make it. Even though you’ll be bringing your water to a near boil before pouring, the difference between tap water and filtered water is profound, if you’re honing in on the finer aspects of coffee taste. A cup of coffee is 95% water, remember?

The major consideration for water in coffee is “softness.” According to the Specialty Coffee Association, this means water that has no odor or color, no chlorine, a pH of 7.0, alkalinity of 40 ppm, and calcium hardness of 50-175 ppm CaCO3. Yikes, right? Sounds like high school chemistry.

In short, you simply want water that’s clean, chlorine-free, and soft. Soft water means water with a lower concentration of minerals. However, water with no minerals whatsoever isn’t good either, since a tiny bit of minerals helps to bring out coffee flavor. 

In general, any bottled or filtered water will be better and tap water for your coffee, but it depends on the tap water quality where you live. If you’re really serious about using the correct water, charcoal-filtered water is perhaps the top standard in coffee-making, and another option is to use distilled or reverse osmosis water and then treat it with a mineral additive.

If you're someone who enjoys brewing coffee and want to take it to the next level, you might want to try Third Wave Water. It adds a perfect balance of minerals to your brew, and can also be used for tea. 


Third wave water coffee additive

Take Notes

If you’re really working on finding the perfect brew, be sure to take notes on the process. Learn from your mistakes and successes and you’ll hone in on that perfect batch much, much faster.

Frequently Asked Questions

How much coffee do I need for 2 cups of Chemex?

It depends on how big you want your cup of coffee to be, of course. A single standard US cup equals eight fluid ounces, but many people prefer smaller or larger cups of coffee, and Chemex measures their “cups” as five ounces, not eight. It’s also worth noting that you’ll lose a small amount of water during the filtration process as the water soaks through the coffee grounds. 

To brew two large cups of Chemex coffee, the amount of coffee you’ll want to use is approximately 34 grams of coffee grounds (or coffee beans) and 510 grams of water (that’s 17.2 oz of water). Like we discussed above, we’re getting that amount using the default 1:15 ratio. 34 grams of coffee grounds x 15 = 510 grams of water.

Likewise, for one cup of Chemex, you’ll use somewhere around 25 to 28 grams of coffee grounds, depending on your desired strength. We’ll use our 1:15 ratio to find the necessary water, which in the case of 25 grams will be 375 grams of water, or 13.2 oz, (because 25 x 15 = 375). In the case of 28 grams of coffee grounds, we’ll need 420 grams of water (14.8 oz), via the same math.

Now, this is obviously a little more than that standard of eight ounces per cup of coffee, but given the water loss during the filtration process and the fact that a little extra never hurts, we’ve found this amount of grounds-to-water to be near perfect.


How much coffee do you put in a 3 cup Chemex?

The proportions we use here are the same as discussed above. We’ll use a 1:15 coffee grounds-to-water ratio, though again, that’s only our starting recommendation. Other coffee lovers commonly use 1:18 ratios, for example.

The important thing to remember here is that a 3 cup Chemex doesn’t really equal 3 cups of coffee (well, it can, but it depends on how small you like your cups of coffee). We find that a 3 cup Chemex really only makes around 1 to 2 cups of coffee. A 6 cup Chemex coffee maker, on the other hand, maxes out around 3 to 4 cups.

By that mark, we’ll take 25 grams of coffee grounds and 375 grams of water (13.2 oz), to start off with our 3 cup Chemex carafe. Alternatively, 25 grams coffee and 375 grams (13.2 oz) of water is another decent starting amount.


How much coffee do you put in a 6 cup Chemex?

We’ll use a 1:15 coffee grounds-to-water ratio which is our initial recommendation for Chemex beginners. Experiment from here to find the perfect ratio for you.

Like we mentioned above, your 6 cup Chemex won’t really equal 6 full cups of coffee... unless we’re talking Euro-style cups nearing the espresso variety. You’ll probably only reach around three to four sizable cups of coffee using a 6 cup Chemex coffee maker. 

By that mark, we’ll take 50 grams of coffee grounds and 750 grams of water (24.5 oz) for our 6 cup Chemex. This is pretty close to the maximum amount of coffee and water a 6 cup Chemex can take, so if it feels like too much, some folks start around 45 grams of coffee (675 grams of water), and that works, too!


How much coffee do you put in an 8 cup Chemex?

Again, we’ll use a 1:15 coffee grounds-to-water ratio, which is our initial recommendation for Chemex beginners. Experiment from here to find the perfect ratio for you.

For our 8 cup Chemex, we like to use 60 grams of coffee grounds and 900 grams of water (31.7 oz). 900 grams of water results in the highest water level you’ll be able to get into an 8 cup Chemex, so if you’re having trouble, try lowering the ratio a bit.

Wondering how to improve the Chemex brewing experience?

We make a variety of Chemex accessories that make your Chemex coffee maker and brewing process more efficient and effective. 

From carafe lids and warming cozies to keep your coffee warm and flavorful to a compact, stylish storage caddy to keep your Chemex organized... if you’re a Chemex owner, you’ll appreciate the myriad ways we’ve managed to improve upon the Chemex experience.

Shop Now

We also have a useful guide which discusses the Best Chemex Accessories, which includes filters, lids, kettles and more!



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