Espresso Flow-Rate Control for Consistent Shots Across Puck Variations
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Solution Overview
Problem
Existing espresso machines lack the ability to accommodate variations in the physical coffee puck, leading to inconsistencies in espresso shots due to factors like grinder performance, bean selection, and humidity, resulting in variable shot volume, crema quality, and flavor, which requires baristas to repeatedly adjust settings and waste coffee.
Innovation Solution
A method and system that dynamically control the flow rate of water during pre-infusion and extraction, using pre-infusion and extraction tables to adjust flow rates based on puck permeability, pressure, and user inputs, ensuring consistent shot quality by maintaining precise control over water flow and pressure across the puck.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If pressure control and pressure profiles are used to extract coffee, then the extraction process can be automated, but the system cannot accommodate variations in puck permeability leading to shot inconsistency
Solution Approach 1:
The system continuously measures actual flow rate through the puck and compares it to the target flow rate, then adjusts pump pressure in real-time to compensate for variations in puck permeability. This closed-loop feedback control ensures consistent extraction despite changes in coffee characteristics.
Solution Approach 2:
The system transitions from static pressure control to dynamic flow rate control, where the pump pressure is continuously adjusted during extraction to maintain a constant target flow rate. This dynamic adaptation allows the system to respond to real-time variations in puck permeability.
2Reliability
If baristas manually adjust grinder settings to accommodate bean and humidity variations, then shot quality can be optimized, but time and coffee are wasted during repeated adjustments
Solution Approach 1:
The system automatically compensates for variations in coffee characteristics by measuring actual flow rate and adjusting pump pressure in real-time, eliminating the need for manual grinder adjustments. The system serves itself by adapting to different beans and humidity conditions without barista intervention.
Solution Approach 2:
Instead of changing grinder settings, the system changes the pump pressure parameter dynamically during extraction to maintain target flow rate. This allows optimization of shot quality through pressure adjustment rather than requiring time-consuming grinder reconfiguration.
3Reliability
If baristas monitor shot parameters to determine when to stop extraction, then shot quality can be controlled, but barista attention is occupied during the shot
Solution Approach 1:
The system uses flow rate sensors and control algorithms to automatically monitor and control extraction parameters, determining when to stop the shot based on pre-programmed criteria. This automated monitoring frees the barista to perform other tasks while maintaining shot quality control.
Solution Approach 2:
The system replaces the barista's manual monitoring and decision-making with automated electronic sensors and control algorithms. The mechanical/manual process of watching and stopping the shot is substituted with electronic flow rate measurement and automatic pump control.
4Extent of automation
If volumetric dosing is used to control water volume, then the end point can be automated, but the system does not control how water moved through the puck
Solution Approach 1:
The system transitions from static volumetric dosing to dynamic flow rate control, where the pump adjusts pressure in real-time to maintain a constant target flow rate through the puck. This ensures precise control of water movement throughout the extraction process, not just the total volume.
Solution Approach 2:
The system uses flow rate sensors to continuously measure actual water flow through the puck and provides feedback to the pump control system. This closed-loop control ensures the target flow rate is maintained throughout extraction, providing precise control over how water moves through the coffee.
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
This approach reduces shot-to-shot variability, minimizes the need for frequent grinder adjustments, and maintains consistent shot weight and time across a range of puck permeabilities, reducing waste and improving the overall espresso-making process.
Implementation Method 1
The pump pressure is dynamically adjusted to deliver water at a constant flow rate through the puck
Implementation Method 2
an actual flow rate sensor to measure an actual flow rate of water through the puck
Data Source
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AI summary
An espresso brewing system to dynamically control the flow rate of water during pre-infusion and extraction to improvement shot consistency. Simple user controls create a programmatic "brewing environment" which allows shots to be very repeatable and shared, allowing shots to be reproduced on other machines with this system.