Correlating Espresso Quality with Coffee-Machine Parameters by Means of Association Rule Mining

Daniele Apiletti,Eliana Pastor

doi:10.3390/electronics9010100

Daniele Apiletti, Eliana Pastor

Open Access

https://doi.org/10.3390/electronics9010100

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Journal: Electronics	Publication Date: Jan 4, 2020
Citations: 8	License type: CC BY 4.0

Affiliation: Polytechnic University of Turin

Abstract

Coffee is among the most popular beverages in many cities all over the world, being both at the core of the busiest shops and a long-standing tradition of recreational and social value for many people. Among the many coffee variants, espresso attracts the interest of different stakeholders: from citizens consuming espresso around the city, to local business activities, coffee-machine vendors and international coffee industries. The quality of espresso is one of the most discussed and investigated issues. So far, it has been addressed by means of human experts, electronic noses, and chemical approaches. The current work, instead, proposes a data-driven approach exploiting association rule mining. We analyze a real-world dataset of espresso brewing by professional coffee-making machines, and extract all correlations among external quality-influencing variables and actual metrics determining the quality of the espresso. Thanks to the application of association rule mining, a powerful data-driven exhaustive and explainable approach, results are expressed in the form of human-readable rules combining the variables of interest, such as the grinder settings, the extraction time, and the dose amount. Novel insights from real-world coffee extractions collected on the field are presented, together with a data-driven approach, able to uncover insights into the espresso quality and its impact on both the life of consumers and the choices of coffee-making industries.

Highlights

Coffee, besides being one of the most popular beverages all over the world, remains a ritual in many cities, during work breaks and recreational times, both at home and in local business activities.While coffee is a general term for a key ingredient of many different drinks, espresso is among the most discussed variants in terms of quality issues.Espresso is at the forefront of establishing the gold standards in terms of professional coffee brewing
The dataset has been pre-processed according to the following data cleaning procedures, to popular approaches [3,47,48]: (i) a domain-driven threshold-based filter has been applied, and (ii) a data-driven additional filter has been used
The second data-driven filter aims at removing extreme values that, even if acceptable, would skew the results

Summary

Introduction

Espresso is at the forefront of establishing the gold standards in terms of professional coffee brewing. In some countries, such as Italy, where 97% of adults drink espresso daily [1], espresso quality is a main driver for consumers’ habits in the city, able to move people from a coffee shop, namely a “bar”, to another nearby. The primary focus on espresso quality is confirmed by a memorable slogan from a past advertising campaign of a top-level Italian coffee brand: “Espresso is a pleasure. If it isn’t good, what pleasure is it?”

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Discussion

Conclusion