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More precision on Castillo v Caturra

2015-04-22 Comments Off on More precision on Castillo v Caturra

Earlier this month, I had the honor of presenting to the SCAA Symposium the preliminary results of the work we did with friends in the research and specialty coffee communities on the Colombia Sensory Trial.  The following day, the Colombian Coffee Hub published this summary of my presentation, which concluded with my observation that the data showed Castillo can be good.  Very good.

Indeed, it does appear that the Trial delivered important validation of the quality potential of a variety that has been consistently maligned in a certain segment of the specialty market.

I think it is important, however, to articulate three caveats to the Colombian Coffee Hub summary.

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Colombian Coffee Hub

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N = 21

First, the small sample size for the trial—just 21 farms—did not allow us to generate the statistical robustness we had hoped for. The preliminary results I presented using scores from a small number of 2014 harvest samples are not statistically significant.  They don’t tell us anything about the relative quality potential for Castillo or Caturra outside of Colombia. Or even outside of Nariño. Or even what these coffees are capable of for the 2015 harvest.

QUANTITATIVE, QUALITATIVE and QUANTIFYING THE QUALITATIVE

Second, the findings reported on in the Hub’s summary reflect only the quantitative results of the two cupping panels we held at Intelligentsia Roasting Works in Chicago in October 2014 and January 2015.  They do not incorporate the insights of the sensory analysts at Kansas State University who applied the new SCAA/WCR sensory lexicon to this work.  Their contributions “quantify the qualitative” by and are vitally important complements to the average scores I reported.

CASTILLO and CATURRA: EQUAL BUT DIFFERENT

And third, we should introduce a bit more precision to the conclusion you publish in the final paragraph in boldface: “There are no evidence of differences between Caturra and Castillo when we’re talking about taste or flavor.”  That is not exactly what the data showed.

What the data from the cupping panels showed was that there was no statistically significant difference in the average scores that the two varieties earned during the cupping panels. And the cupping panel data showed that there was no statistically significant difference between the average scores for any of the specific sensory categories included in the analysis. The fact that the two coffees earned roughly the same average overall and category-level scores does not mean there is no difference between the two varieties in taste or flavor. In fact, this is precisely what the very preliminary data from the Kansas State work suggest—that while Castillo and Caturra can both be good, a good Castillo has a different taste or flavor than a good Caturra.

The sensory analysts at KSU were able to succeed where the cuppers failed to generate statistically significant evidence of separation bewteen the two varieties. They did not show that one variety was better than another but that there is a substantial and quantifiable difference in the sensory characteristics of the two varieties. A good Castillo was fruity but not citric, with notes of dark chocolate and roasted nuts, while a good Caturra was floral with cocoa and caramel notes. This research is still ongoing—I look forward to the opportunity to share more information with readers of Coffeelands and the Colombian Coffee Hub when I have it.