Brewing Methods
Sources: The Coffee Brewing Handbook by Rob Lingle (SCA, 2011)
Every coffee brewing method uses hot water to dissolve and extract soluble flavouring compounds from ground coffee. However, the method — particularly how water contacts the grounds, how long it stays in contact, and how the grounds are separated — fundamentally shapes the type and amount of flavouring material removed. (source: SCA Coffee Brewing Handbook)
The Six Methods
1. Steeping
Coffee grounds in a container are mixed with hot water, left in contact for a specified time, then separated from the brew.
- Contact time depends on: particle size, water temperature, agitation, and separation method
- Examples: French press, cupping (SCA protocol), siphon (partial)
- Produces rich body from brew colloids (oils and fine particles not filtered)
- Risk: over-extraction if grounds remain in contact too long
2. Decoction
Loose grounds are mixed with water that continues to boil for an arbitrary time.
- Temperature: 100°C (212°F); turbulence from boiling
- Complete extraction usually occurs due to elevated temperature and extreme turbulence
- Results in over-extraction in virtually all cases — bitterness and astringency dominate
- Example: traditional Turkish coffee (though technically boiled briefly, not simmered continuously)
- Not recommended for quality brewing alongside percolation (both are explicitly flagged as over-extraction methods in the SCAA framework)
3. Percolation
Grounds are placed in a chamber; a pump recirculates hot water and then extract through the grounds repeatedly.
- Contact time depends on grind size, water/extract temperature, and recirculation rate
- Successive passes through grounds increase extraction — risk of over-extraction is high
- Not recommended by the SCAA for quality results — over-extraction from recirculation
4. Drip Filtration
Grounds are placed in a filtering device; hot water flows through the grounds once, extracting as it passes.
- Water contacts grounds only once — the fundamental difference from percolation
- Extract drips from the brew chamber into a collection vessel
- Contact time depends on: flow rate into chamber, grind size, chamber shape, filter type
- The standard SCAA-evaluated brewing method; the basis for the Coffee Brewing Control Chart
- Examples: paper filter pour-over (V60, Chemex), flat-bottom basket filter, commercial drip brewers
5. Vacuum Filtration
A two-chamber device using steam pressure and vacuum.
- Steam pressure forces hot water from lower chamber up through a filter into the upper chamber containing grounds
- Escaping vapour and stirring create turbulence and agitation
- When heat is removed, steam condenses in the lower chamber creating a vacuum that pulls the beverage back down through the filter, leaving grounds behind
- Variation on steeping; produces a very clean cup
- Example: siphon/vacuum brewer
6. Pressurized Infusion (Espresso)
Water between 2–10 atmospheres of pressure is forced through compacted grounds.
- Brewing temperature: 88–92°C (190–195°F) — slightly lower than other methods
- Rapid brewing time: 20–30 seconds per cup
- Very fine particle sizes essential for uniform extraction under pressure
- Produces a multi-phase system: solution, emulsion (emulsified oils), suspension (ultra-fine particles), and foam (CO₂ bubbles)
- Results in extremely high solubles concentration — not directly comparable to filter coffee on the CBCC scale
- Not covered by The Coffee Brewing Handbook, which focuses exclusively on filter brewing
(source: SCA Coffee Brewing Handbook)
Comparison Table
| Method | Contact Type | Typical Temp | SCAA Endorsed? | Body | Clarity |
|---|---|---|---|---|---|
| Steeping | Immersion | 92–96°C | Yes | High | Low–Medium |
| Decoction | Boiling immersion | 100°C | No (over-extracts) | High | Low |
| Percolation | Recirculating | 92–96°C | No (over-extracts) | High | Low |
| Drip Filtration | Single-pass | 92–96°C | Yes | Depends on filter | High (paper) |
| Vacuum Filtration | Immersion + vacuum | 92–96°C | Yes | Medium | High |
| Pressurized Infusion | Forced through | 88–92°C | Separate standards | Very high | Low |
Filtering and Body
The filter medium separating grounds from brew directly affects body — the mouthfeel and tactile weight of the beverage.
Body is created by brew colloids: insoluble oils and micro-fine bean fibre particles that pass through the filter into the beverage. These colloids trap soluble flavouring materials and gases, releasing them time-delayed on the palate.
| Filter Type | Clarification | Body | Notes |
|---|---|---|---|
| Paper (cone or flat-bottom) | Highest | Lowest | Absorbs oils; can impart taste if stored poorly |
| Cloth | High | Medium | Requires maintenance; absorbs oils over time |
| Woven wire screen (100–200 mesh) | Medium | High | Allows oils through; frequent cleaning required |
| Perforated metal plate | Low | Highest | Minimal filtration; many fines pass through |
See SCA Coffee Brewing Handbook for full filter detail.
Relevance to Kaiserblick
Kaiserblick roasts exclusively for filter extraction — its light roast profiles are developed to reveal origin character through the gentle, long extraction of drip filtration and steeping methods. This is the opposite end of the spectrum from dark roast espresso.
Kaiserblick’s export customers in Germany and France typically use drip filter (Chemex, V60, batch brewers) and filter machine systems. The NCC standard of 60–70g/liter applies to these market contexts. See Brewing Standards.