Brew Library / Brew Guides
Chemex
Brew Guide
The Chemex does not merely brew coffee. It clarifies it. Every variable you control grind, pour rate, water temperature shows up undeniably in the cup. There is nowhere to hide. That is precisely what makes it one of the most rewarding brewers to master.
Invented by chemist Peter Schlumbohm in 1941, the Chemex is both a laboratory flask and a serving vessel. Its iconic hourglass shape and thick bonded paper filters produce one of the cleanest, brightest cups of any manual brew method. Light roasts with complex floral and fruit notes find their fullest expression here. If the AeroPress rewards experimentation, the Chemex rewards patience and precision.
Understanding the Device
How the Chemex Works
The Chemex is a pour over brewer. Hot water is poured over a bed of ground coffee held in a thick paper filter. Gravity pulls the brew through the filter and into the lower vessel below. There is no pressure, no immersion beyond the pour, and no mechanical assistance. Just water, coffee, and time.
What distinguishes the Chemex from other pour over methods like the Hario V60 is its filter. The Chemex bonded filter is 20 to 30 percent thicker than standard filters. This extra thickness removes nearly all coffee oils and fine particles from the brew, producing a cup that is exceptionally clean, light-bodied, and transparent in flavour. You will taste the coffee clearly every note of the origin, the roast, and the water.
The thick filter also means longer drain time, which naturally increases extraction. This is why Chemex works best with a slightly coarser grind than a V60 the extended contact time compensates, and going too fine will stall your brew and over-extract.
What You Need
Equipment
The Chemex setup requires slightly more attention than most brew methods. Each piece of equipment has a direct impact on your results.
Brewer
Chemex
3, 6, 8, or 10 cup sizes. The 6-cup is the most versatile for 1 to 2 servings.
Filter
Chemex Bonded
Square or circle, natural or bleached. Bleached filters have a slightly cleaner taste profile.
Grinder
Burr Grinder
Medium-coarse grind. Consistent particle size is critical the thick filter amplifies any unevenness.
Kettle
Gooseneck
Not optional here. Precise, controlled pours directly determine extraction evenness in a Chemex.
Scale
0.1g Precision
Weigh both coffee and water. The Chemex is unforgiving of dose or volume errors.
Timer
Dedicated Timer
Total brew time is your primary quality indicator. Track it every single time.
The Filter
Choosing Your Filter
The filter is the defining element of Chemex brewing. Understanding the difference between filter types helps you choose the right one for your coffee and your preference.
Option A
Natural (Unbleached)
- Slightly more paper taste if not rinsed thoroughly
- Eco-conscious choice, no chemical bleaching
- Requires a longer, more thorough rinse
- Performs identically once fully rinsed
- Light brown colour when held to light
Recommended
Bleached (White)
- Minimal paper taste even with a quick rinse
- Slightly cleaner flavour baseline in the cup
- Preferred in professional and competition settings
- Oxygen-bleached low environmental impact
- Easiest to work with for beginners
Regardless of which filter you use, always rinse with hot water before brewing. Place the folded filter in the Chemex, pour at least 100ml of hot water through it slowly, then discard that water before adding your coffee. This step is not optional it removes paper taste, preheats the vessel, and seats the filter against the glass so it does not collapse during brewing.
The Recipe
Starting Ratios
The Chemex standard recipe uses a 1:15 to 1:17 ratio. Because the thick filter retains more coffee than other methods, slightly increasing the dose relative to other pour overs is common practice. The following recipe is for a 6-cup Chemex producing two generous servings.
30g
Coffee
Medium-coarse grind
500ml
Water
90 to 94°C
1:16
Ratio
Balanced and clean
4 min
Total Time
Target window
Water temperature for Chemex sits in a narrower window than AeroPress. Because the brew is slow and the filter is thick, the water cools slightly during the pour. Start at 92 to 94°C for medium roasts and 94 to 96°C for light roasts. Dark roasts do well at 88 to 91°C to avoid over-extracting through the extended contact time.
Pour Structure
The Pour Timeline
The Chemex rewards a structured pour sequence. Unlike some pour over methods that advocate a single continuous pour, breaking the water addition into phases gives you more control over extraction and allows CO₂ to off-gas properly during the bloom. Below is the recommended pour sequence for a 30g / 500ml recipe.
Time
Action
Amount
Running Total
0:00
Bloom pour
60ml
60ml
0:45
First main pour
150ml
210ml
1:30
Second main pour
150ml
360ml
2:15
Final pour
140ml
500ml
3:30 – 4:00
Drawdown complete
,
Serve
If your drawdown is completing significantly faster than 3:30, your grind is too coarse. Slower than 4:30 and your grind is likely too fine, or your filter was not rinsed properly and is partially clogged. Total brew time is your single best dial-in indicator on the Chemex.
The Method
Step by Step
Chemex brewing is methodical. Each step builds on the last. Skipping or rushing any phase will show up clearly in your cup.
1
Fold and Rinse the Filter
Open the Chemex filter so that three layers are on one side and one layer on the other. Place the three-layer side facing the spout this reinforces the filter where it contacts the pour spout channel and prevents it from collapsing. Rinse thoroughly with at least 100ml of hot water. Discard the rinse water by pouring it out through the spout.
Three layers face the spout. This is the most commonly skipped setup detail in Chemex brewing. The single layer side on the pour side collapses under pressure and restricts flow.
2
Grind and Dose
Grind 30g of coffee to medium-coarse coarser than a V60, similar to a coarse table salt. The grind should feel gritty between your fingers without being sandy. On most grinders this sits 2 to 4 clicks coarser than your V60 setting. Place the Chemex on your scale, add the coffee to the filter, and tare to zero.
Level the bed. Gently tap or shake the Chemex after adding coffee so the grounds settle flat. An uneven bed creates uneven extraction during the pour.
3
The Bloom
Start your timer. Pour 60ml of water (double the coffee weight) slowly and evenly over all the grounds. Begin from the centre and spiral outward, then back in. The goal is to saturate every ground without flooding the bed. You will see the coffee swell and gas begin to off-gas this is CO₂ escaping. Wait 45 seconds for the bloom to complete before your first main pour.
Good bloom, better cup. Freshly roasted coffee (within 2 weeks of roast date) will bloom aggressively. Coffee older than 4 weeks may barely bloom at all. Both are fine to brew, but the bloom phase tells you something about your bean's freshness.
4
First Main Pour
At 0:45, begin your first main pour. Add 150ml of water slowly in a steady spiral motion from the centre outward. Keep your gooseneck kettle low and close to the coffee bed about 5 to 8cm above the grounds. Pour at a rate that keeps the water level consistent in the filter without flooding it. Do not pour down the sides of the filter.
Never pour on the filter paper directly. Water hitting the filter walls bypasses the coffee bed and creates channelling a path of least resistance where water shoots through unevenly, under-extracting the surrounding grounds.
5
Second and Final Pours
At 1:30, add your second pour of 150ml using the same technique. At 2:15, complete the brew with the final 140ml pour. After each pour, allow the water level to drop by roughly half before adding the next. This controlled, pulsed pouring maintains consistent contact time between water and coffee throughout the entire brew. Resist the urge to speed it up.
6
Drawdown and Removal
After your final pour, let the remaining water drain fully through the filter. This should complete between 3:30 and 4:00. Once the last drops fall and the filter shows a damp, flat coffee bed with a slight dome in the centre, remove the filter in one clean movement and discard. Do not press or squeeze the filter this forces fine particles through and muddies the cup.
The flat bed tells you a lot. A perfectly flat, even coffee bed after drawdown means even extraction. A bed with visible channels, cracks, or high edges on one side means your pour was uneven. Adjust your next brew accordingly.
7
Swirl and Serve
Before serving, give the Chemex a gentle swirl to integrate any minor temperature variations between the first and last brewed liquid. The Chemex retains heat well in its glass vessel, but serving promptly after brewing preserves the most complex aromatic notes. Taste it at temperature before assuming it needs adjustment a Chemex cup at 65 to 70°C often reveals flavours that disappear when it cools too far.
Diagnose Your Cup
Variables and Troubleshooting
The Chemex communicates directly through brew time and cup flavour. Use both to identify and fix issues before your next brew.
Problem
Sour, Sharp Cup
Under-extraction. Common with grind too coarse, water too cool, or bloom too short. Light roasts are especially prone if temperature is low.
Grind finer by 2 to 3 clicks, raise temperature to 93 to 95°C, extend bloom to 60 seconds.
Problem
Bitter, Dry Finish
Over-extraction. Grind too fine for the thick filter, causing extended contact time beyond the optimal range.
Grind 2 to 3 clicks coarser. Total brew time should not exceed 4:30.
Problem
Brew Taking 6+ Minutes
Grind far too fine, filter not rinsed properly, or grounds migrated to clog the filter walls during pouring.
Grind noticeably coarser. Ensure filter rinse is thorough. Pour only onto the coffee bed, never the filter walls.
Problem
Brew Finishing in 2 Minutes
Grind too coarse, dose too low, or filter collapsed on one side creating a bypass channel.
Grind finer, check filter placement with three layers facing the spout, increase dose by 2g.
Problem
Flat, Lifeless Cup
Coffee is stale (more than 4 to 6 weeks post-roast), or water temperature was too low to extract volatile aromatics.
Use fresher coffee. Raise water temperature. The Chemex's clean profile amplifies staleness more than any other brewer.
Problem
Paper Taste in Cup
Filter not rinsed sufficiently, or rinsed with water that was too cool to fully saturate the thick bonded paper.
Rinse with water at full boil temperature. Use at least 150ml for the rinse. Discard all rinse water before adding coffee.
Brew It Slow.
Then Brew It Slower.
Most people who struggle with the Chemex are rushing it. They pour too fast, they skip the bloom, they pull the filter before the drawdown is done. The Chemex is not a device that responds well to impatience. The moment you accept that this brew takes four full minutes and commit to every pour with attention, the results shift noticeably.
One thing I always recommend: try brewing the Chemex exclusively with single origin light roasts specifically washed Ethiopians or Kenyan AA grades. The Chemex filter's ability to strip oils and sediment is exactly what these coffees need. Their florals and citrus notes come through with a clarity that no other brewer produces at home. You get jasmine, bergamot, bright acidity, a tea-like body flavours that other brewers partially mask. If you want to understand what a coffee truly tastes like at origin, brew it on a Chemex.
The other habit worth building: keep a small notepad beside your Chemex setup. Write down your brew time, dose, and grind setting after every session. The Chemex is sensitive enough that even a two-degree temperature change or a slightly different pour pace will shift the cup. Tracking your brews means you can reproduce a great cup and diagnose a bad one without guessing.
The Chemex Rule
"If you want to taste the coffee exactly as the farmer and roaster intended it no oils, no sediment, no interference brew it on a Chemex. It is the most honest brewer in your cabinet."
Quick Reference
Chemex at a Glance
Coffee Dose
28 – 32g
Start at 30g
Water Volume
450 – 500ml
500ml standard
Temperature
90 – 96°C
Light roast: higher
Grind Size
Medium-Coarse
Coarser than V60
Total Time
3:30 – 4:30
4:00 is ideal
Ratio
1:16
Clean and balanced
Brew Checklist
Three filter layers facing the spout
Rinse filter with at least 100ml hot water
Level the coffee bed before blooming
Bloom 45 to 60 seconds before first pour
Pour only onto the coffee bed, not the filter walls
Target total brew time of 3:30 to 4:30
Remove filter without squeezing
Swirl Chemex before serving