Why does boutique coffee science clean the coffee machine regularly?

One of the questions often asked in the coffee industry is "how often should I clean the coffee machine?" The answers are varied, some say once a day, others say once a week, and still others say according to the amount of coffee.

But does anyone really know the answer to this question? None of these answers is supported by public research. To answer this question, the authors conducted an experiment to study the relationship between the cleaning frequency of an espresso machine and the taste of coffee. First of all, in this experiment, the factors that may affect the taste of coffee are: the consistency of the quality and quality of roasted coffee beans, the consistency of baristas' techniques and techniques, the amount of coffee used, the degree of grinding of coffee beans, the ratio of coffee to water, and the extraction time; the ability and reliability of the cup judges; and the performance of the espresso machine.

It is not easy to find a coffee shop that can be tested, because the coffee shop must strictly follow the experimental requirements, and a set of coffee machines cannot be cleaned at all. In the course of the experiment, we must try our best to control other conditions to ensure that the cleanliness of the coffee machine is the only variable that affects the taste of coffee, so the experiment must ensure strict requirements.

Michel'sEspresso, a Sydney cafe that uses an average of 6kg of coffee a week, volunteered to take part in the experiment. Azkoyen Vienna 3 coffee machines, grinders and producers are grouped according to the following:

Group 1: clean with Cafetto ®Espresso Clean once a day

Group 2: clean with Cafetto ®Espresso Clean once a week

The third group: unclean during the experiment.

The experiment lasted 19 days, and each set of coffee machines was recycled to ensure that each group was used evenly.

Through the coffee machine temperature and pressure measuring instrument, we check the temperature and pressure of each machine to ensure that the temperature and pressure do not affect the experimental results, as shown in the table below.

In order to ensure the consistency and reliability of coffee taste comparison, three coffee experts formed a jury: winner of the 2007 Australian Coffee Cup Test Competition, organizer of the Hazel De Los Reyes; World Barista Championship, and Instaurator, Executive Director and author before the Emily Oak; World Barista Championship.

For the same reason, Scott Callaghan, winner of the 2007 Australian barista contest, extracted coffee and made cappuccinos in this test. The coffee used in the experiment was Michel's Espresso mixed coffee beans, and the experimental time was 22 days after roasting.

Each group of espresso will be randomly assigned to the judges, who will then use the espresso's standard score of 1mur10 (1 very bad, 10 very good) to compare the following factors of coffee: the color of coffee secreting oil; consistency of coffee secreting oil; coffee secreting oil persistence; taste balance; technical balance; overall taste / impression.

The three coffee judges scored the three groups of coffee, and then summed up the final score for each group. At the end of the 19-day trial period, the scores of each group were calculated. Ratings and comments are also shown in the lower left corner.

The conclusion of the test shows that it is obvious that the coffee machine is clean and the taste of espresso will be greatly improved.