Apr 8 2012

photoAs you enjoy your coffee each morning, do you ever wonder where it comes from? Did you know that when coffee is first harvested it looks drastically different? The bean that helps millions of people wake up every day is actually the seed of a cherry. Right off the tree, coffee is a small, round, dark-red piece of fruit that resembles a grape. So how does this become a cup of coffee? After harvest, the cherry needs to be processed. The various processing methods that are used in the coffee industry each affect the taste of the bean in their own way.

In the wet or washed method, the fruit is removed from the seed which is then dried. This generally produces a clean, lightly bodied, acidic cup and is widely used in Central American nations such as El Salvador and Guatemala, among other regions. After harvest, the cherries are brought to the wet mill where they are sorted in tanks of water. The ripe fruit is dense and sinks to the bottom of the tanks while the unripe and defective cherries tend to float at the surface to be removed along with any other unwanted material.

photoThe ripe cherries are then pushed through screens that scrape off the outer skin and a portion of the inner pulp. At this point there are several options for how to remove the remaining pulp. The coffee can be pushed into fermentation tanks where the sugars in the fruit are broken down, allowing the pulp to be washed off in fresh water. Machines can also be used to remove the pulp in a more predictable uniform manner that avoids the risk of taking on bad flavors that the fermentation process can produce if not executed properly.

Although this option requires expensive machinery, it uses substantially less water than the fermentation process. This, however, can have a negative effect on the taste because the amount of time that the bean is in contact with the fruit is reduced. Alternatively, the coffee can be moved to the drying patios, foregoing the fermentation process or the pulping machines. Drying the bean with a small amount of pulp remaining gives the coffee a fruity, full bodied, less acidic taste. This method is known as the pulp natural process.

The final step is to dry the bean so that it will become stable, which will allow it to be shipped and stored until it is roasted. Drying is generally done on raised patios under the sun where it is observed and tended to in order to avoid mildewing or developing mold. In regions where rain is an issue, drying machines may be used to speed up the process, which can take up to four weeks to reach the desired 10% moisture level.

The dry or unwashed process has been around since people first began producing coffee and is still commonly used in many growing regions such as Brazil and Ethiopia, for example. Using this method, the beans are sorted and moved directly to the drying patios. The outer layers become hard when dried and are removed by hand or by hulling machine. This method produces a low-acid, full-bodied, earthy-tasting beverage.

There are several outer layers that must be removed from the coffee bean. The skin, pulp and parchment are all taken off before the coffee leaves the producing region. Only the silver skin is left adhered to the bean when it is exported. This layer comes off in the roasting process and all that remains is the brown bean, ready to be brewed into your favorite cup of coffee.

So whether it is the bright blueberry notes of Ethiopian Sidamo or the rich milk chocolates of El Salvador Santa Leticia that you love, it is safe to assume that the processing method is largely to thank.

About the author: Kelly is the Assistant Coffee Roaster for McMenamins.
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