Coffee Capsule Particle Sizing for Stable Extraction Pressure
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Solution Overview
Problem
Existing coffee capsules with open exit areas and loosely packed coffee result in uncontrolled beverage preparation due to low extraction pressure, leading to inferior coffee quality with excessive wateriness and lack of foam, as water rushes through the capsule, causing uncontrolled fluid flow and low CO2 content.
Innovation Solution
A coffee capsule with a preselected particle size distribution of roast and ground coffee (10th percentile: 20-60 µm, 50th percentile: 400-600 µm, 90th percentile: 700-1000 µm) and compacted coffee to prevent particle displacement, combined with strategically placed exit openings and a porous exit filter, ensuring controlled fluid flow and higher extraction pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If loosely packed coffee is used in an open capsule, then ease of manufacture is improved, but extraction pressure is insufficient leading to inferior coffee quality
Solution Approach 1:
The coffee is pre-compacted into a coffee bed with controlled density and particle size distribution before being placed in the capsule. This preliminary action ensures that during beverage preparation, the coffee bed maintains sufficient resistance to water flow, generating the necessary extraction pressure for high-quality coffee, while still being easy to manufacture using compaction equipment.
2Reliability
If particle size is reduced to improve extraction, then coffee quality improves, but particles may clog exit openings causing flow restriction
Solution Approach 1:
The coffee bed is designed with a specific particle size distribution where smaller particles (10-50 µm) are concentrated in regions that benefit from high extraction, while larger particles (50-200 µm) are positioned to maintain flow channels. The exit openings are strategically designed with dimensions (0.2-0.5mm) that allow fine particles to pass through while preventing excessive clogging, achieving both high coffee quality and adequate fluid flow.
3Reliability
If coffee bed is compacted to increase extraction pressure, then coffee quality improves, but beverage preparation time increases
Solution Approach 1:
The coffee bed is compacted to an optimal density range (0.6-0.8 g/cm³) that balances extraction pressure generation with water permeability. This controlled compaction parameter ensures sufficient resistance to build extraction pressure for high-quality coffee while maintaining adequate porosity for water flow, thereby achieving both high extraction pressure and acceptable beverage preparation time.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution results in improved coffee quality with enhanced oil concentration, Dry Matter Accumulation, and a stable foam layer, while maintaining a consistent brewing time, by preventing particle displacement and ensuring controlled fluid flow through the compacted coffee bed and exit filter, leading to a higher extraction pressure and better CO2 content.
Implementation Method 1
a porous or perforate third wall closing the circumferential first wall at a second, open, end opposite the second wall arranged for draining the prepared beverage from the capsule
Implementation Method 2
the extractable product in the inner space of the capsule has particles falling within a preselected range of distribution by weight... ensuring controlled fluid flow and higher extraction pressure
Data Source
Figure 1
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AI summary
Capsule (2) for preparing a predetermined quantity of beverage suitable for consumption using an extractable product, for instance roast and ground coffee, comprising a circumferential first wall (14), a second wall (16) closing the circumferential first wall at a first end (18), a perforate and/or porous third wall (20) closing the circumferential first wall at a second, open, end (22) opposite the second wall arranged for draining the prepared beverage from the capsule, wherein the first, second and third wall enclose an inner space (24) comprising the extractable product, wherein the extractable product in the inner space has particles falling within a preselected distribution by weight, wherein a 10th percentile of the particle size is 20 - 60 μm, wherein a 50th percentile of the particle size is 400-600 μm and wherein a 90th percentile of the particle size is 700-1000 μm. The invention further relates to a method for manufacturing such a capsule, a system comprising such a capsule for preparing a beverage and a method for preparing of a beverage.