Brewing Cold Brew Coffee With A Chemex

Quick Answer

• Use a coarse grind for cold brew to prevent over-extraction and bitterness.
• A 1:8 coffee-to-water ratio is a good starting point, but adjust to your taste.
• Steep for 12-24 hours at room temperature or in the refrigerator.
• Filter the cold brew through your Chemex with a paper filter to remove fine particles.
• Dilute the concentrate with water or milk to your preferred strength before serving.
• Always start with fresh, good-quality coffee beans for the best flavor.

Who This Is For

• Coffee enthusiasts looking to explore cold brew methods beyond traditional immersion brewers.
• Home baristas who already own a Chemex and want to utilize it for a different brewing style.
• Those who appreciate a smoother, less acidic coffee and are willing to experiment with longer brew times.

What to Check First

Brewer Type and Filter Type

Your brewer is a Chemex, a pour-over device known for its elegant design and thick paper filters. For cold brew, the Chemex will primarily act as a filtration system to separate the coffee grounds from the brewed liquid. The thick Chemex filters are excellent at trapping fine coffee particles, which can lead to a cleaner, less silty cup. Ensure your Chemex is clean and free of any residual oils or flavors from previous brews, especially if you’ve used it for hot coffee.

Water Quality and Temperature

Cold brew relies on time rather than heat to extract flavor, so water quality is paramount. Use filtered water or good-tasting tap water. Avoid distilled water, as it lacks minerals that contribute to flavor extraction. For cold brew, the temperature is, by definition, cold. This means room temperature (around 68-72°F) or refrigerator temperature (around 40°F). Brewing at room temperature can lead to slightly faster extraction, while refrigerator brewing might result in a cleaner, more subtle flavor profile.

Grind Size and Coffee Freshness

The grind size for cold brew is crucial. You’ll want a coarse grind, similar to what you’d use for a French press. A grind that’s too fine will lead to over-extraction, resulting in a bitter, muddy brew that can clog your filter. Conversely, a grind that’s too coarse might lead to under-extraction and a weak, watery coffee. Always use freshly roasted coffee beans and grind them just before brewing for the best aroma and flavor. Stale coffee will produce a dull and uninspired cold brew.

Coffee-to-Water Ratio

The ratio of coffee to water is highly personal but serves as a critical starting point. For cold brew, a common ratio is 1:8 (e.g., 1 part coffee to 8 parts water by weight). This creates a concentrate that you can dilute later. Some prefer a stronger concentrate, like 1:4, while others might aim for a less concentrated brew closer to a 1:10 ratio. Experimentation is key to finding your ideal strength. Weighing your coffee and water is the most accurate way to achieve consistent results.

Cleanliness/Descale Status

A clean brewing setup is non-negotiable for great-tasting coffee, especially cold brew where flavors can become concentrated. Ensure your Chemex carafe and any containers used for steeping are thoroughly washed and dried. If you’ve been using your Chemex for hot coffee, it might benefit from a descaling process periodically to remove mineral buildup, which can affect taste. Check your brewer’s manual for specific cleaning and descaling instructions.

Step-by-Step: Brewing Cold Brew Coffee With A Chemex

1. Weigh and Grind Your Coffee: Measure your whole coffee beans. For a 1:8 ratio and a 32 oz brew, you might start with 4 oz (113g) of coffee. Grind the beans to a coarse consistency, resembling breadcrumbs or sea salt.

• What “Good” Looks Like: Uniformly coarse grounds with no fine dust.
• Common Mistake: Grinding too fine. This will lead to a bitter, muddy brew and can clog your filter.
• Avoid It: Use a burr grinder set to its coarsest setting, or look for grounds that are visibly large and distinct.

2. Prepare Your Chemex: Place a Chemex paper filter into the top of your Chemex brewer. Rinse the filter thoroughly with hot water to remove any papery taste and to preheat the carafe. Discard the rinse water.

• What “Good” Looks Like: A clean, preheated Chemex with the filter securely in place.
• Common Mistake: Not rinsing the filter. This can impart a papery taste to your coffee.
• Avoid It: Pour hot water over the entire filter, allowing it to drip into the carafe, then empty the carafe.

3. Add Coffee Grounds to a Steeping Container: Transfer your coarsely ground coffee into a large jar, pitcher, or French press. This container will be used for the steeping process, not the Chemex itself.

• What “Good” Looks Like: All your grounds are contained in one vessel, ready for water.
• Common Mistake: Adding grounds directly to the Chemex at this stage. The Chemex is for filtering, not steeping.
• Avoid It: Use a separate, non-reactive container like glass or stainless steel for steeping.

4. Add Water: Pour your cold or room-temperature filtered water over the coffee grounds. Ensure all grounds are saturated. For a 1:8 ratio with 4 oz of coffee, you would add 32 oz (4 cups) of water.

• What “Good” Looks Like: All coffee grounds are wet and appear to be blooming slightly.
• Common Mistake: Inconsistent saturation. Some grounds might be dry, leading to uneven extraction.
• Avoid It: Pour water gently and stir the grounds with a spoon or chopstick to ensure complete saturation.

5. Stir Gently to Ensure Saturation: Give the mixture a gentle stir to make sure all the coffee grounds are fully submerged in the water. Avoid vigorous stirring, which can agitate fine particles.

• What “Good” Looks Like: A slurry where all coffee particles are in contact with water.
• Common Mistake: Over-stirring. This can break down grounds and increase bitterness.
• Avoid It: Use a slow, deliberate stirring motion for about 10-15 seconds.

6. Cover and Steep: Cover the container tightly with a lid or plastic wrap. Let it steep for 12 to 24 hours. You can steep at room temperature or in the refrigerator. Longer steeping times will yield a stronger, more concentrated brew.

• What “Good” Looks Like: The mixture is undisturbed, steeping away.
• Common Mistake: Not covering the container. This can lead to dust or other contaminants entering the brew.
• Avoid It: Use an airtight lid or seal the container securely with plastic wrap.

7. Prepare the Chemex for Filtration: After steeping, place the Chemex on a stable surface. Insert the rinsed paper filter.

• What “Good” Looks Like: Chemex is ready with a properly seated filter.
• Common Mistake: Filter collapsing or not properly seated. This will cause grounds to bypass the filter.
• Avoid It: Ensure the filter is opened into a cone shape and sits snugly in the Chemex spout.

8. Slowly Pour the Steeped Coffee: Gently pour the steeped coffee mixture into the Chemex filter. Pour slowly and in stages, allowing the liquid to filter through. Don’t fill the Chemex to the brim if it’s very full.

• What “Good” Looks Like: The liquid is slowly dripping into the Chemex carafe.
• Common Mistake: Pouring too quickly or all at once. This can overwhelm the filter and lead to a messy overflow.
• Avoid It: Pour in a steady, controlled stream, stopping if the filter begins to fill too high.

9. Allow to Fully Drip: Let the coffee completely drip through the filter. This can take several minutes. You may need to gently swirl the grounds in the filter to encourage drainage if it seems slow.

• What “Good” Looks Like: The last drips are coming through, and the carafe contains clear cold brew concentrate.
• Common Mistake: Rushing the process or removing the filter too soon. This means you’re leaving concentrate behind.
• Avoid It: Be patient and let gravity do its work.

10. Discard Grounds and Filter: Once dripping has stopped, carefully remove the filter containing the coffee grounds and discard them.

• What “Good” Looks Like: A clean filter with spent grounds, and a carafe of cold brew concentrate.
• Common Mistake: Leaving the filter in too long and letting sediment seep back into the brew.
• Avoid It: Remove the filter promptly after the last drip.

11. Dilute to Taste: Your Chemex now holds cold brew concentrate. Dilute it with cold water, ice, or milk to your desired strength. A common starting point is a 1:1 ratio of concentrate to diluent (e.g., 1 part concentrate to 1 part water).

• What “Good” Looks Like: A perfectly balanced cup of cold brew that is smooth and not too strong or weak.
• Common Mistake: Drinking the concentrate straight. It’s very strong and can be unpleasantly intense.
• Avoid It: Always dilute the concentrate before serving, adjusting the ratio until it tastes right to you.

12. Serve and Enjoy: Pour your diluted cold brew over ice. Add any desired sweeteners or milk.

• What “Good” Looks Like: A refreshing, smooth, and delicious cold coffee beverage.
• Common Mistake: Not serving it cold. Cold brew is best enjoyed chilled.
• Avoid It: Serve immediately over plenty of ice.

Common Mistakes (and What Happens If You Ignore Them)

Mistake	What It Causes	Fix
Using a fine grind	Bitter, over-extracted, muddy coffee; clogged filter	Use a coarse grind (like sea salt or breadcrumbs).
Not rinsing the Chemex filter	Papery taste in the final brew	Rinse the filter thoroughly with hot water before adding coffee grounds.
Using stale or poor-quality beans	Flat, dull, uninspired flavor	Use freshly roasted, high-quality whole beans and grind them just before brewing.
Inconsistent coffee-to-water ratio	Inconsistent strength and flavor from brew to brew	Weigh your coffee and water for precise, repeatable results. Start with a 1:8 ratio.
Over-steeping (beyond 24 hours)	Bitter, astringent, and unpleasant flavors	Stick to the 12-24 hour range. Taste a small sample at 12 hours and adjust based on preference.
Under-steeping (less than 12 hours)	Weak, watery, under-extracted coffee	Ensure you steep for at least 12 hours. Taste and extend steeping if it’s too weak.
Pouring steeped coffee too fast	Grounds bypass the filter, leading to a silty cup	Pour slowly and in stages, allowing the filter to drain properly.
Not diluting the concentrate	Extremely strong, undrinkable coffee	Always dilute the concentrate with water, ice, or milk to your preferred strength.
Using tap water with strong flavors	Off-flavors transferred to the cold brew	Use filtered water or bottled water that tastes good on its own.
Not cleaning the Chemex thoroughly	Lingering old coffee oils or flavors	Wash your Chemex immediately after use and descale periodically if mineral buildup is an issue.

Decision Rules

• If your cold brew tastes bitter, then you likely used too fine a grind or steeped for too long, because these lead to over-extraction.
• If your cold brew tastes weak or sour, then you may have under-steeped it or used too coarse a grind, because this leads to under-extraction.
• If your final cup is silty or has a lot of sediment, then your filter may have been overwhelmed or your grind was too fine, because grounds passed through.
• If you want a brighter, cleaner cup, then try brewing in the refrigerator, because cooler temperatures can slow extraction and highlight subtle notes.
• If you prefer a richer, bolder flavor, then try brewing at room temperature for the longer end of the steeping window (20-24 hours), because slightly warmer temperatures can extract more.
• If your cold brew concentrate is too strong after brewing, then dilute it with more water or ice, because that’s the purpose of making a concentrate.
• If your cold brew concentrate is too weak, then you can try steeping for a few more hours or using a slightly finer grind next time, because these will increase extraction.
• If you notice a papery taste, then you likely skipped rinsing your Chemex filter, because the paper itself imparts flavor.
• If your coffee tastes dull, then use freshly roasted beans and grind them just before brewing, because freshness is key to vibrant flavor.
• If you’re finding your brew inconsistent, then start weighing your coffee and water for accuracy, because volume measurements can vary.

FAQ

What is the best grind size for cold brew in a Chemex?

For cold brew, you want a coarse grind, similar to what you’d use for a French press. This prevents over-extraction and ensures a clean filter.

How long should I steep cold brew?

A good starting point is 12-24 hours. Longer steeping times result in a more concentrated and intense flavor. Taste at 12 hours and adjust based on your preference.

Can I use my Chemex to steep the cold brew?

No, the Chemex is used for filtering the cold brew concentrate after it has steeped in a separate container. Steeping directly in the Chemex can lead to uneven extraction and a clogged filter.

What is the ideal coffee-to-water ratio for cold brew?

A common starting ratio is 1:8 (coffee to water by weight), which creates a concentrate. You’ll dilute this concentrate to your preferred strength. Feel free to experiment.

Do I need to use hot water at any point?

Yes, you should rinse the Chemex paper filter with hot water before brewing to remove papery taste and preheat the brewer. The steeping process itself uses cold or room-temperature water.

How do I make cold brew less bitter?

Ensure you’re using a coarse grind, avoid over-steeping (beyond 24 hours), and make sure your coffee is fresh. Over-extraction is the main cause of bitterness.

Can I brew cold brew in the refrigerator?

Yes, brewing in the refrigerator is a great option. It can result in a cleaner, more subtle flavor profile compared to room-temperature brewing.

How should I dilute my cold brew concentrate?

Dilute the concentrate with cold water, ice, or milk to your desired strength. A 1:1 ratio of concentrate to diluent is a common starting point.

What This Page Does Not Cover (And Where to Go Next)

• Specific recommendations for coffee bean origins or roast profiles for cold brew. (Next: Explore different coffee origins and roasts to find your favorites.)
• Detailed information on water chemistry and its impact on coffee extraction. (Next: Research water filtration systems and their benefits for coffee brewing.)
• Advanced techniques like Japanese-style iced coffee or flash chilling. (Next: Look into methods that involve brewing hot coffee directly over ice.)
• Troubleshooting specific machine issues if you’re using an automatic cold brew maker. (Next: Consult the manual for your specific cold brew appliance.)