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Buying Specialty Green Coffee

The green coffee seller is responsible for grading coffee beans before sending the coffee to the buyer.  Once graded, "Exceptional" and "Specialty" green coffee beans can still have problems that are not necessarily accounted for in coffee grading.  These coffee "defects" are less serious, but harm the potential of the coffee.  You can tell a great deal about the processing conditions of a coffee by looking at the appearance of the green coffee beans.  Although cupping is the definitive way to check for problems, a good prognostic tool is to compare coffee beans.

Things to Consider when Buying Coffee:

1.  The green coffee beans should be of nearly equal size 17/18, 15/16, 13/14 etc, be similarly shaped, and have a similar color.  The reason for this has to do with how evenly the coffee will roast which will affect the appearance and taste of the roasted coffee.  Smaller coffee beans will roast differently than larger beans resulting in an uneven cup.  Uneven coloring hints toward drying problems, whereas uneven shapes may indicate a mixing of cultivars.

2.  Ensure that the producer separates coffee lots by both geographic area and coffee varietal.  These lots should be harvested, processed, and cupped separately before blending in the silos.

3. Washed Arabica coffees should be even and bright.  The coffee beans should not have an uneven or dull color.  If they do, they are likely to have been dried or processed incorrectly.  Coffee processing is essential for specialty green coffee. If the green coffee beans look faded, the cup quality will be faded.

4.  Inquire about the coffee drying conditions on the coffee estate.  If they seem to have invested a significant amount of time into ensuring that they are drying the coffee properly, the coffee quality will generally show this in the cup.  Improper drying on patios or in mechanical dryers can usually be observed visually.  Rapid drying in mechanical dryers results in dull or brown coffees.  Coffee beans that are mottled (or quakers when roasted) result when the coffee is dried too quickly, spread too thin on the patios, or not rotated as frequently as recommended.  Some people recommend drying coffee on patios first to dry the skin, then transfer to mechanical dryers, and then bring the coffee back to the patios for the final drying.  They believe that this helps improve color.  Others send coffee beans to the dryers several times, while in between drying sessions they allow the coffees to rest in silos so that the moisture content of the bean can come to equilibrium.  This is important since the outside of the coffee bean will dry faster than the inside of the bean.  Inquire about the temperature used on the dryers.  Is it over 42C?  If so you can expect a dull or baked cup, resulting in a coffee grade that is less than desirable.

5.  For all coffees, inquire about the coffee processing.  Make sure they process the coffee estate is processing green coffee beans immediately upon harvesting.  Otherwise you are guaranteed a fermented cup since coffee begins fermenting immediately upon picking.  Ask how they use the fermentation tanks and why?  Do they separate out coffees that float to the top of the tanks during fermentation?  After pulping, do they separate coffees by density before they add them to the tanks?  Only coffee estates that have dedicated a significant amount of time to improving coffee quality will know why these steps are important and necessary.  If coffee pulp is present in the tanks during processing, it can result in brownish tinges on the green coffee beans.  This is also indicative of harvesting over-ripe coffee cherries.

6.  Natural (dry) processed coffees will often be covered in brown silverskin which has attached itself to the bean.  In Brazil they call this a "fox bean" and it is not considered a defect.  Novice classifiers might expect this type of bean to be a defect, but if you can remove a portion of the silver-skin by rubbing on the black sorting mat it is not considered a defect.  Green (under ripe) coffee also has a silver-skin attached to it, but this cannot be removed by simple rubbing.  In a washed coffee, fox beans may indicate sour, fruity, or Rio tastes.  This should be confirmed in the cup and not visually.

7.  Do the coffee beans have a little pink skin covering them or inside the crack of the bean?  In some areas this is a serious defect which most people do not consider to be a defect.  Since it is not a part of the green coffee classification, these beans could be passed on to the buyer as specialty coffee.  These coffee beans should be separated and cupped to determine if the defect is serious.

8.  Are the coffee beans whitish or faded around the edges?  This is likely a result of insufficient drying or storage in humid conditions.  The cup will be bland and ordinary.  These white marks are also observed in coffees that have not been dried evenly.  The portion of the bean that has a whitish tone has higher moisture than the other parts of the bean.  Whitish or discolored coffee beans can also result from oxidation, contact with the earth, or polluted waters.

9. Before you buy green coffee beans, smell them. Ferment and smoke damage can be easily detected at this point, whereas they might be more subtle when roasted.

10. Pick up the green coffee beans. How do they feel? If they feel glass-like and fragile, they have been over dried or dried at too high of a temperature. If they are pliable, they have not been dried sufficiently and should be rejected since mold growth at this point is unavoidable.

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