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Milling, Grading & Shipping

By Carson Parodi on

We’ve discussed all the most common methods coffee is processed, but how does it eventually get to our importers, to us at Mill47, and then to you? This is the final step in green coffee’s long journey from farm to cup.

Dry Milling / Hulling. Once coffee completes its final drying stage it needs to be milled to remove what is called the parchment layer, or hull. You can think of this as a thin, dry, crackly, outer shell that protects the coffee beans. Some coffees in this “pergamino” state (the Spanish word for parchment), are shipped with this crispy outer layer still intact.

Sorting. After coffee is hulled, it is often sorted based on size and color and to remove any defective beans that may have slipped through the cracks. This final effort toward quality is usually done by hand or with computerized optical sorters (in the larger, more commercial farms, anyway)

Grading. Grading coffee is sometimes denoted by “screen size” which refers to the size of the holes in large sieves through which beans pass through. A screen of 15+, like the Colombia Geisha we have in, means that all the beans are bigger than 15/64 of an inch. The more uniform size lends itself to a more even roast and typically better cup, but the direct correlation of screen size and quality from coffees around the globe is not a clean equation.

Even after these mechanical methods are employed, the beans are usually checked once again by human eyes to determine quality, remove defects, and sort out any debris. Dan likes to talk about his days roasting coffee in the 90’s, when finding the occasional rock, bullet, and even human tooth were not uncommon…Needless to say, today’s specialty grades definitely have their benefits.

Bagging & Logistics. We’ve discussed the storage of green coffee beans in an earlier post so we won’t delve into it much here, but green coffee beans are “hygroscopic” meaning they absorb what’s around them — mostly moisture. Out on the open seas there are radical environmental changes that can compromise the coffee beans during transport.

For this, green coffee is packed in hermetic, heavy gauge, “GrainPro” bags that help maintain moisture stability as well as keep out harmful insects and pests. These bags go inside burlap jute sacks for added strength during transport.

Finally, about 275 70kg (150lb) bags, totalling 42,000 pounds, are stacked into a 20-foot shipping container which gets loaded onto a cargo ship, likely headed to New Jersey, Houston, New Orleans, Seattle or Oakland, where most of our coffee is landed and stored.

Every single coffee we buy comes in a GrainPro bag inside of a burlap sack.

Perspective. When one considers the amount of effort and manual labor needed to prepare just one single coffee bean for roasting, it’s actually quite sad how cheap green coffee is. It’s difficult to imagine how our dollars translate into living wages for the countless folks involved.

We hope the more we peel back the veil on this industry, the more we can ensure workers are paid better, and explain that doing so uplifts everyone in the supply chain and encourages the production of better coffees.

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