• QA 237
    Why do some producing countries use altitude in their descriptions and others bean size?
    Why do individual producing countries classify their coffees differently? After all, whilst bean size and altitude are both quite important, certain countries only specify one of these two aspects. For example, screen (bean) size for Colombia and altitude for Costa Rica. Do these two aspects (bean size and altitude) not differ considerably in terms of quality?
    Asked by:
    Student - Switzerland

    Altitude and bean size each contribute to 'quality' in different ways. Like variety and soils, altitude is an inherent quality factor in that it largely determines bean density. Bean size is a differentiating factor in that i) larger beans usually (but not always) have better 'quality' than smaller ones from the same batch and ii), stipulating a minimum screen size ensures a more even roasting process (very small beans roast more quickly than large ones).*

    Many 'official' descriptions simply indicate in general terms what a buyer may expect. Basically they attempt to ensure (to the extent possible) that individual exporters play by a certain set of qualitative rules. Hence we simply see names linked with 'grown between … and … metres' (= altitude) or names linked with 'minimum screen …' (= minimum bean size). And of course buyers (roasters) know from experience what a coffee from a particular country thus described should do for them in terms of 'quality' = the taste or 'cup' as the trade calls it. **

    However, these official or semi-official descriptions are only the first step when it comes to 'quality'. In a general sense they help separate different coffees and facilitate pricing in that most market players can easily establish the ruling quotation for the better-known origins and descriptions. But when it comes to non-standard coffees (either very high top quality or, low qualities and small to very small beans) then this is not so easy. Price then very much depends on the individual buyer's expectations in terms of 'quality'. To note also that many formal descriptions do not refer to cup quality, relying instead on specifying the type and number of defects that is allowed. This means that 'quality' can vary between individual exporters and this is why contracts often stipulate additional requirements as, for example, strictly clean cup.
    In the end roasters decide for themselves, on arrival, whether a particular parcel is acceptable to them or not, irrespective of the description it may carry. Thus, official 'certificates of quality' or 'descriptions' do not absolve an exporter from his responsibility to deliver the correct 'quality'.

    Individual country classifications are easily viewed by visiting www.supremo.be  - click on their 'Coffee Encyclopaedia'. For a full discussion on 'coffee quality' read Chapter Eleven of The Coffee Guide.

    * For an explanation of 'screens' and 'screen sizes' see topic 11.05.08 of The Coffee Guide. Coffee crops grown at altitude take longer to mature which results in higher bean density that in turn usually produces better cups, for example with more acidity. As a result of the physical separation process larger bean grades usually do not contain the immature beans that produce bitter or astringent cups. However, whereas altitude and bean size are indicators of quality they do not automatically guarantee a good cup.

    ** Taking Colombia as an example we see: by screen size: 
    Supremo max 5% under screen 17 but over screen 14.
    Supremo screen 18+  max 5% under screen 18 but over screen 14.
    Excelso Extra max 5% under screen 16 but over screen 14
    Excelso EP max 2.5 % under screen 15 but over screen 12
    (the preparation may vary to 5% or 8% depending on the client's requirements)
    U.G.Q."Usual Good Quality": max 1.5% under screen 14 but over screen 12

    From Costa Rica we see, by altitude
    SHB Strictly hard bean: from 1200 -1650 m, and HB Hard bean: from 800 - 1100 m

    Posted 14 July 2010

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