How Full Can You Fill a Chemex? (Solved & Explained!)

A Chemex Coffee Maker is a convenient and rewarding way to brew coffee, but if you’re planning on serving more than one cup of coffee, you may be wondering: how full can you fill a Chemex?

According to the Chemex company, a Chemex coffee maker comes in cup sizes 1, 3, 6, 8, and 10, while each cup is considered to be 5 US fluid ounces. This means that a Chemex coffee maker can hold up to 400 ounces of fluid. Most Chemex coffee recipes recommend filling your Chemex up with fluid until it is barely below the wooden handle of the Chemex.

Though Chemex coffee makers are popular, they can seem intimidating, especially if you’re used to using an automatic or electronic coffee maker. In this article, we’ll cover how a Chemex coffee maker works and how full your Chemex should be, as well as covering a few frequently asked questions so you can get the best out of your coffee maker!

How Does a Chemex Work?

A Chemex is a type of coffee-making container, classified as a “pour-over” style of coffee brewer. It is a time-honored piece of equipment, having been manufactured in the year 1941.

A Chemex may look beautiful with it’s glass body and wooden neck, but it also tends to look intimidating. In order to decide how full you should fill your Chemex, a good understanding of the way it works can be helpful.

How Pour-Over Coffee Works

Pour-over coffee brewing like the kind a Chemex is great for is not automatic. It gets its name from the fact that the person making the coffee must control the heating, pouring, and aim of the water themselves.

Pour-over brewing’s controlled, hands-on approach extracts the flavor from coffee grounds, making them more rich by the time they enter a mug. This is because the science of brewing coffee involves something called “blooming” the coffee grounds themselves, which an automatic machine cannot do.

Blooming

Blooming is the word used to refer to what happens when hot water is poured on freshly ground coffee. If you’re able to bloom your coffee mixture correctly, you’ll see bubbles form on the top of the liquid.

These bubbles are actually the same that you might see in seltzer or a favorite soda: they are a form of carbonation. Carbonation causes coffee to expand (which is also why wet coffee grounds are so much bigger than dry coffee grounds.) That expansion, in turn, helps the coffee coming out of the grounds to taste even and rich in flavor. 

The reason pour-overs like the Chemex Coffee Maker bloom so much better than the automatic versions is because the person making the coffee can control certain variables. How hot the water is, for example, and how fresh the coffee grounds are; these are important factors in successful blooming!

How to Use a Chemex

Now that we’ve covered the specifics behind how a pour-over like Chemex Coffee Makers work, and how important blooming the coffee is, let’s go over how to actually use one! Check out the steps below.

1. Heat the Water – This needs to be done in a separate kettle. The temperature for your ideal coffee brew is up to you, but in order to properly bloom your coffee, it is a good idea to wait until the water is at 200 degrees Fahrenheit. Use three times the water that you do coffee grounds.
2. Grind Your Coffee – A Chemex Coffee Maker benefits from coffee grounds that are ground on a medium-coarse setting. This is because they use a paper filter which already restrict water flow, so coffee grounds don’t need to be as dense.
3. Position Filter – Chemex filters have one side which is three-layered; this side should face the spout. Before adding coffee grounds, wet the filter on its own with hot water. It will not only warm the glass bottom of the Chemex, but get rid of any paper taste!
4. Add Coffee Grounds – Simply shake the desired amount of coarse coffee grounds into the paper filter, making sure to leave a bed of grounds that is even.
5. Pour the Water – This is the moment when blooming will occur; be sure to only pour enough to get all of the grounds wet, allowing it to bloom for 30 seconds. Then pour in a slow circle until the water is an inch from the top. Finally, add water until the kettle is empty or the Chemex has water settling just below its wooden handle.
6. Cleanup and Enjoy – After the Chemex is full, you’ll have freshly brewed coffee! Simply remove the filter resting on top for easy pouring and enjoy a cup of coffee rich in flavor.

How Full Should a Chemex Be?

A Chemex Coffee Maker is designed to hold a certain amount of cups of coffee. However, the Chemex company considers a cup to be 5 US fluid ounces. They have produced Chemex Coffee Makers that can hold 1, 3, 6, 8, and 10 of these 5 fluid ounce-cups.

To be sure you are brewing enough water to fill your Chemex Coffee Filter, simply multiply the number of cups your Chemex is made to hold by five ounces. This number will be the amount of ounces of water you’ll want to bring to 200 degrees Fahrenheit. 

For example, if you have a 6-cup Chemex Coffee Maker, you’ll want to heat 30 ounces of water in a separate kettle.

If you’ve correctly calculated how much liquid you’ll be pouring over that delicious coffee, your Chemex should be just full enough for the coffee level to stop at the wooden collar around the container.

Summary

Now that we know how a Chemex Coffee Maker works, we can accurately answer the question: how full should a Chemex be? A Chemex Coffee Maker’s strength is in its pour-over style. A pour-over coffee brew is characterized by rich flavors and the control the brewer has over the final product. 

In addition to providing space for the brewer to have their own access to the coffee grounds and to pour their own water, a Chemex Coffee Maker is constructed so that the perfect amount of fluid will leave the Chemex full only to its wooden handle.