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The Role of Numerical Data in Coffee

Hello, I'm Atahan Kaygusuz. I am the head roaster of Flora & Fauna. Today, I would like to talk about the role of the numerical data that we can analyse when obtaining coffee liquid. How effective is the numerical information that we can measure such as TDS, extraction, Agtron value, particle size distribution in the sensory analysis of our liquid coffee?


Recently, I have been conducting research on the effect of the results of the sensory analysis of a numerically under-extracted coffee on people and determining the preferred one by comparing it with coffees with ideal extraction values. I first tested this issue by testing it on people around me and had the opportunity to test it on many participants during the 2023 İzmir Coffee Festival.

At our booth, I brewed six different coffees of our own company in under and standard extraction rates and had them blind tasted. Of the 131 people who participated in the survey, 89 people preferred the under extracted coffee, while 42 people chose the coffee in the ideal extraction range. This represents a ratio of 67.93% and 32.07%. This result is a confirmation that I advocate that liquid coffee should be evaluated on the basis of sensory analysis, not on numerical data.


However, Jonathan Vaz Matias, an SCA instructor whose opinion I have always valued, stated that the data I obtained should not be compared on the extraction value, but on the brew rate. Because I determined the extraction values of the coffees before the festival and placed them in certain ranges, but I did not have the opportunity to measure these values in the festival area. Since the brewing parameters were the same, the variable was only the ratio; I used a ratio of 1:12.5 for under-extracted brews and 1:17 for ideal extracted brews. He stated that since I could not measure TDS and extraction values, I should make a ratio comparison due to missing data. This explanation was correct and appropriate.



TDS, another measurable parameter, is the second topic of my article. Have you ever brewed the same coffee with two waters with different TDS ranges, keeping all parameters constant? Although I did not make a conscious comparison, I came across an interesting situation.


I brewed the same coffee with Kaltun Madran water (45 ppm, pH 6.8, total alkalinity 0, total hardness 0) and Third Wave Water classic profile water (180 ppm, pH 6.4, total alkalinity 40, total hardness 0-25). What was the result? Kaltun Madran (1.70 TDS, 16.83 extraction rate) and Third Wave Water (1.69 TDS, 16.57 extraction rate) were very close to each other. We tried this test with both immersion and percolation methods and the numerical results were close in both cases. However, although the water values were numerically different from each other, the liquid coffee we obtained had similar numerical data with the same parameters, which revealed different results in sensory analysis.






Although the results of liquid coffee are almost the same, the minerals that we cannot measure in water differentiate the character of the coffees. This supports the need to emphasise sensory analysis rather than relying on numerical data.


In conclusion, while numerical data helps us to take reference with sustainability and standardised data, sensory analysis is a fundamental factor to make the real evaluation of coffee.


We could have evaluated the coffees within the same framework by making an assessment based on the result. However, we saw that there were extremes in the sensory analysis. I would like to recall a good example of the relationship between water, recipe and ratio, as Can said. Indeed, the effect of water on the result is as important as the recipe and the ratio. However, in my opinion, the most important is sensory analysis. It is important to be able to analyse all the parameters and to be able to obtain results in a conscious way, but if we cannot evaluate the result sensory, the data we have is meaningless.


Not only me, but also big organisations such as SCA, Coffeemind, Barista Hustle are conducting research and publishing articles on this subject. However, we need to remember that the coffee we process is an organic product, it is presented to people with different cultural habits through different stages.


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