coffee green grading
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10 Things to Look For in Coffee Green Grading

 

SOCIA EUFEMIA GARCIA

When buying green coffee beans, finding the best of the best should be your main objective. Even though you may have seen “exceptional” and “specialty” green coffee beans, they could still have minor defects that you miss – which affects the potential of the coffee. While cupping is one way to check for imperfections, a few things can be practiced in coffee green grading when looking out for spots. We have compiled ten things for you to look for in green grading in this blog. Remember, the small things matter!

  1. Green coffee beans should be sorted according to size, for example, 15/16, 13/14, 17/18, etc. The reason is that the roasted beans will be distributed evenly when they are the same size. Smaller beans will burn differently than giant beans, affecting their appearance and taste. You can measure the length with coffee screens. Q-Grader Adam S. Carpenter stated that the increments increase stepwise by 1/64 inches. The most common diameters of holes range from 10-20, while super small beans fall into 10/64 inch (4mm), and large beans are suspended (not falling through) holes with a 20/64 inch (8mm) diameter. Coffee green grading is extensive work!
  2. Find the primary and secondary defects. Defects can come from anywhere: pre-processing (from the farm and nature), processing (related to human error – mishandling during the seed removal) to storage (while the coffee is sitting in the bag or truck). Primary defects will distinguish the coffee from “specialty” status – even if it's only one or two defects. Some examples of primary defects include entire black, full sour, large stones, medium stones, large sticks, and medium sticks. On the other hand, coffee can still be labeled as a “specialty” even with a few secondary defects. Secondary defects include parchments, insects, small stones, partial sour, and water damage.
  3. Make sure that both geographic area and coffee varietal separate the coffee lots. This ensures that the coffee quality is the same during each process. The coffee is supposed to be harvested, processed, and cupped separately before blended in storage.
  4. The coffee beans should not be dull or uneven in color. Check if the washed coffee beans –especially Arabica, have an even and bright color because it shows that the coffee processing has been exemplary. This is a crucial thing to check since processing is an essential part of green coffee, and if it isn’t done correctly, it affects the quality of the cup.
  5. Coffee quality also depends on the drying process, so make sure that the coffee is dried correctly. The rate will usually show in the cup if the suppliers have done so. Meanwhile, improper drying processes will result in dull and brown coffee – it can be observed visually. Coffee Research Institute states that coffee beans that are blotched (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. Lastly, you should make sure the temperature used in the dryers is less than 42°C since it will be a soft or baked cup if it’s over the number.
  6. Green beans should be processed straight away after harvesting, or else you’ll receive a fermented cup since the fermenting phase begins immediately after picking. Ensure that the suppliers give extra attention to the process by confirming how they use the fermentation tank and whether they separate coffee by density before it sits in the tank.
  7. Confirm if the silverskin or “fox bean” attached to the beans isn’t a defect by cupping it. Silverskin is usually found in natural (dry) processed coffee and isn’t considered a defect in Brazil since you can easily remove it – by rubbing it on the black sorting mat. It’s harder to remove the fox bean under-ripe green beans and cannot easily be removed by simple rubbing, so it can be considered a defect. Silverskin in washed coffees may also indicate sour and fruity tastes, so beans should be verified - not only by visual means.
  8. Check to see if the beans have pink skin covering them. Some people do not consider it a defect since it’s not in the coffee green grading classifications. The beans can also still be classified as specialty coffee. However, this can also be examined as a severe defect and should be cupped to determine the defections.
  9. Check if the coffee beans are whitish or faded around the edge. Several factors can cause this: inadequate drying, humid storage conditions, oxidation, and polluted waters. This discolored coffee will result in bland and ordinary cups as they contain more moisture than other parts of the bean.
  10. Pick up and smell the green beans. Some defects such as ferment and smoke can be identified by smelling in this stage, unlike if it’s done in the cup as it’s more subtle. Over-dried or beans dried in too high temperatures can be determined by picking them up and feeling as if they’re fragile. Meanwhile, supple beans indicate that they’re insufficiently dried.

 

SOCIA CAPACITANDO EN ANALISIS FISICO - SRA SEGUNDA ZURITA

There are many things to be examined during green coffee grading, but the more detailed inspection we do, the better the coffee quality. Even though some of the points we share aren’t included in the official green coffee grading classifications, our suggestions are meant to result in a cup of perfect coffee that will make your customers’ day!


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