Bean Graders – Because They Know Good Beans

Have you ever wondered why some beans make it to your local specialty shop and some don’t? There is actually quite a long process before beans even hit the shelf. Moreover not all the beans are created equal and that’s where the bean graders come into play. Before you get a chance to sip that delicious dark liquid, coffee graders have to put up with hot and tiring journeys, fight the insects, face the hostile governments and endure weeks of frustration and danger to bring you that favorite brew. Well, maybe it’s not quite as adventurous as that, but graders do lead rather interesting lives.

Coffee is graded long before reaching the loading dock. This task is carried out by someone called a ‘Green Coffee seller’. I know what it sounds like, but actually it has nothing to do environmental movement. It’s simply a reference to the color the beans have, before roasting.

There are a number of traits that beans need to be examined for.

They need to be fairly uniform in size and similarly shaped. It is important for helping to ensure an even roast. Beans roast differently depending on their size. When the size of the bean differs the roasting time can’t be adjusted properly, since some will pop and brown before others.

Graders also look for similarity of color. Uneven coloring normally means that beans have dried at different rates. It also indicates that beans may have been mixed from different cultivars, which in return leads to inconsistency in roasting and flavor.

To achieve the proper final results beans have to be separated by geographic region grown and by cultivar. It’s essential that they are harvested, processed and dried separately for the final product to be a fine brew.

Beans retain the best quality when they’re processed soon after harvesting. Coffee beans undergo a kind of fermenting process that will initiate after harvesting. The process is not like fermenting wine – where sugars turn into alcohol, but it nevertheless produces unwanted compounds. Drying prevents this from beginning.

Many processors will float the beans in the water in floatation tanks to separate out defective beans, since different density beans will float at different levels. This is also one of the ways to detect potato defect, which we have written about previously.

Finer beans, however, result from a more time-consuming process called ‘dry processing’. Dry processed beans have a brown ’silverskin’, called a fox bean in Brazil. If the silverskin can be removed by simple rubbing, it’s not a defect, but evidence of this dry process. Under ripe beans, though can also have a silverskin, which can’t be removed by rubbing. Such beans will result in a coffee with a sour taste.

Drying beans is not an easy job, it’s an art all by itself. Estates often boast proudly of the skill and care taken during the process. As well they might. Improper drying often shows. Every now and then economics encourages processors to use harsh mechanical drying techniques. Drying the beans too rapidly or failing to turn them often enough can result in beans with an uneven, mottled appearance.

Properly dried beans will first spend some time on a ‘patio’, to dry the skin, before they’re fed to the mechanical dryer. Truly superior beans will have spent several short stints in the dryer at around 40°C (104°F), rather than one long one. The result is an even color and just the right moisture content.

But that’s not all that graders need to look for.

As the result of inadequate drying or being stored in too humid conditions beans can have a white edge, which will result in a bland cup and graders are on the lookout for it.

Good Arabica coffee beans, the type used in fine coffees, will have an even, bright appearance.

Lastly, they smell the beans. Good beans will have a fresh aroma, but they also try to detect what’s absent along with what’s present. Any improper processing will add a smoky or musty tinge that you don’t want in your cup.

So before you sip that fine brew, take a moment to sense the fine aroma and lift a cup in thanks to bean graders.