• QA 026
    Can mineral fertilization change cup characteristics?
    Are cup characteristics as acidity, body, aroma etc influenced or altered by fertilization - are there any studies to this effect?
    Asked by:
    Grower - Colombia

    From the coffee taster's point of view the answer is yes.  The relationship between fertilization and matters as yield, bean size, bean density etc is beyond the scope of this website in that it concerns pure agronomy. But it is true that marked changes in yield and bean can show up in the cup.

    A healthy, well-nourished coffee tree, free from stress, usually produces good quality, i.e. reasonably sized and dense beans. The cup quality of those beans then depends on the variety, the soil, the altitude, the climate, and on how the coffee is processed. However, the grower is also interested in the yield, the quantity harvested, and so there is a never ending conflict between the wish for 'quality' on the one hand, and 'quantity' on the other. Responsible and correctly developed fertilization programs within the overall tree maintenance cycle can enhance both quality and quantity. But within reason…. It is well to remember that the impact of all fertilization programs should be closely monitored, also on quality! 

    Applying mineral fertilizer where traditionally this has not been the case can sometimes negatively affect the cup, for example in varieties grown in rich volcanic or forest soils that produce delicate flavours in the cup. One would have to be certain that the introduction of mineral fertilizer would not alter such a coffee's traditional cup profile to the extent that established buyers lose interest…

    In high-density (commercial) plantings heavy fertilizing can produce impressive yields but, in the end, this is at the expense of 'quality' with cups losing both body and aroma. This may also make acidity too dominant, thereby producing unbalanced cups. Over-fertilization may even change acidity into thin, metallic bitterness, called 'fertilizer flavour' by some. 

    Posted 15 June 2005

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