Brew Methods Deep Dive
Chemex Technique and Filters
The Chemex is a pour over brewer defined by its iconic glass design and proprietary thick paper filters that produce an exceptionally clean cup. This guide covers filter placement, pouring patterns, ratios, and how to leverage the Chemex's unique filtration for bright, nuanced coffee.
The Chemex Difference
Designed by German chemist Peter Schlumbohm in 1941, the Chemex is simultaneously a brewer and a serving vessel — an hourglass-shaped borosilicate glass carafe with a conical neck and a wood-and-leather collar. It is one of the few coffee makers displayed in the Museum of Modern Art's permanent collection.
What truly distinguishes the Chemex from other pour over drippers is its proprietary bonded paper filter, which is 20-30% heavier than standard pour over filters. This thick paper removes significantly more oils and micro-fines from the brew, producing a cup that is remarkably clean, bright, and almost tea-like in its clarity. Drinkers who prefer a heavy, oily cup should look elsewhere — the Chemex is about transparency and origin character.
Filter Types
Chemex offers several filter options:
- Bonded paper (white) — bleached, no papery taste, produces the cleanest cup. The standard choice.
- Natural paper (brown) — unbleached, requires thorough rinsing to remove residual flavor. Same thickness as white.
- Half-moon filters — designed for smaller Chemex models (3-cup).
- Able Kone — an aftermarket stainless steel filter that allows oils through, changing the Chemex's character entirely. This defeats the purpose of using a Chemex.
Always rinse the paper filter with hot water before brewing. This serves two purposes: it removes any residual paper flavor (even in bleached filters) and pre-heats the glass carafe.
Brewing Technique
Setup
| Parameter | 6-Cup Chemex | 8-Cup Chemex |
|---|---|---|
| Coffee | 30-34 g | 42-48 g |
| Water | 500 g at 93-96°C | 700 g at 93-96°C |
| Grind | Medium-coarse (coarser than V60) | Medium-coarse |
| Total brew time | 4:00-5:00 | 4:30-5:30 |
Filter Placement
Unfold the Chemex filter into a cone. It has three layers on one side and one on the other. Place the three-layer side against the spout — this prevents the filter from collapsing into the pour channel and blocking airflow. Pour hot water through the filter to rinse, then discard the rinse water through the spout.
The Bloom
Add the ground coffee and create a small well in the center of the bed. Pour 60-70 g of water (about twice the coffee weight) in a slow spiral from the center outward. Wait 45 seconds. The Chemex's larger bed requires a slightly longer bloom than a single-cup V60.
During the bloom, the grounds will swell and release CO2. If the grounds barely move, your coffee is likely stale — fresh beans should produce vigorous bubbling.
The Main Pour
Pour in slow, concentric circles from the center outward, stopping about 1 cm from the filter walls. Avoid pouring directly on the filter — water that contacts the paper without passing through coffee dilutes the brew.
For a 6-cup Chemex, pour in 3-4 stages:
- Bloom: 0:00-0:45 — 60 g
- First pour: 0:45-1:30 — pour to 250 g total
- Second pour: 1:30-2:30 — pour to 400 g total
- Final pour: 2:30-3:15 — pour to 500 g total
- Drawdown: 3:15-4:30 — let the bed drain completely
The water level in the Chemex should never rise above the bottom of the wood collar. If it does, you're pouring too fast.
Drawdown
The thick Chemex filter creates a slower drawdown than standard pour over filters. A total brew time of 4:00-5:00 minutes for a 6-cup batch is normal. If drawdown exceeds 5:30, grind coarser. If the bed drains before 3:30, grind finer.
Why Grind Coarser for Chemex
The thick paper filter creates more flow resistance than a V60 or Kalita filter. If you use the same grind for Chemex as for V60, the brew will stall — water sits too long on the grounds, producing an over-extracted, bitter cup. Compensate with a coarser grind, roughly the texture of kosher salt.
Achieving Clarity
The Chemex's clean cup is its defining trait. To maximize clarity:
- Use fresh, filtered water — 75-150 ppm TDS, no chlorine
- Rinse the filter thoroughly — at least 100 g of hot water
- Maintain a steady pour rate — inconsistency creates uneven extraction
- Do not agitate the bed — no stirring, no swirling; let the water do the work
- Serve promptly — the carafe has no insulation; coffee cools quickly in glass
Cleaning and Storage
The Chemex glass carafe is dishwasher-safe but fragile. Hand washing with a bottle brush and hot water is safer. The wood collar and leather tie should be removed before washing (untie the leather cord and slide off). Coffee oils build up on glass over time — a weekly soak in a solution of hot water and baking soda keeps the carafe pristine and ensures no residual flavors contaminate future brews.
Store the Chemex dry and uncovered. Glass does not absorb odors, but trapped moisture can develop musty smells.