Defects Common to Green Coffee – The First Step to Quality Coffee
There are many factors that play into coffee quality. From growing, to processing, shipping, storing, roasting, and brewing, there are many stages that coffee goes through before it reaches your hands in hot liquid form. This article is my attempt to focus in on the growing aspect of our coffee’s quality and the defects that we try to avoid.
Coffee beans are the seeds of a coffee shrub, and they grow inside of a cherry that the coffee shrub produces. Since coffee is a produce, it’s susceptible to defects. Just like an apple from the grocery store might be beautiful and firm, or soft and ugly, coffee beans can have a variety of defects that reduce the quality of that coffee.
Here is a list of defects that exist in green coffee and their effects on the flavor in the cup.
Black: This is when the green coffee bean looks black instead. This results from insufficient water while the cherry is developing, picking overripe cherries from the ground, or other reasons. If one of these gets roasted, there could be an “off-flavor” that adds a bad sour note to otherwise good coffee. It could also work the mute the rest of the cup.
Sour: The green bean here looks more red, yellow, or brown. This results from poor production methods, like a delay between harvest and process or letting the bean ferment too long. This can make a roast seem like it’s underdeveloped, resulting in sour or grassy flavor tones.
Dried Cherry: This bean got overlooked during the depulping stage, and it was dried and packed with the cherry still on. It’s pretty obvious to catch, but if a dried cherry makes it into the roaster, it burns to an absolute crisp. If it makes it through the grinder and into the cup, I imagine there would be a very smoky char flavor in the cup, though this has never happened to me.
Fungus: This is in the form of mold that grows within and on the coffee bean. Mold will usually infect entire batches of coffee during shipment or storage under elevated moisture levels. This will taste moldy in the cup or have strong earthy, organic flavors. Sorry, I don’t have a pic of a moldy bean – it’s never happened to me!
Insect damage: The most common insect damage to coffee is the Coffee Borer Beetle. This tiny little monster will bore into the coffee cherry and into and through the seed. He will bore back and forth until either harvest or pesticide. This results in tiny little bore holes going through the coffee bean. Results in the flavor of the cup vary from unnoticeable, muted flavor, to sour notes.
Foreign Objects: This is when a coffee sample has rocks, sticks, or even glass mixed in with it. This is a result of bad production, when a producer will allow this foreign matter to contaminate his or her crop. Rocks and glass won’t make it passed the grinder, and you know what sticks taste like.
Quaker: These are immature beans, and they’re usually smaller than the rest in the batch. This results from poor nutrition supplied to the coffee cherry, inhibiting its growth. You’d think this would be more common given that coffee stunts your growth … … …
Broken or Crushed: This happens when the coffee is mishandled somehow. When a coffee bean breaks, it doesn’t roast evenly or correctly. The result in flavor is simply unbalance, a flavor that doesn’t fit in with the optimal flavors.
Withered: This is a malnourished coffee seed that doesn’t develop properly within the cherry. These can mute the flavor and acidity of the coffee or make it taste dirty.
Importers grade green coffee by visually analyzing samples of it before roasting. If the samples have too many of these visible defects, then the specialty market rejects it, and the producer must try to sell in the commodity market. However, if the samples pass the test, then buyers will evaluate the coffee by roasting it and tasting. If the flavor of the coffee scores an 80 or above according to SCA protocol, then the producer is able to sell on the specialty market at a premium price well over the commodity market rate.
Driftwood Coffee Company
So where do we fit in the picture? One of our main jobs is sourcing our coffee well. The best roaster in the world can’t roast coffee defects away. They all negatively affect the flavor of the coffee. So if we want to offer excellent coffee, we’ve got to purchase excellent green coffee. There are lots of coffees available to us, and if we were primarily concerned with our profit margin, we would buy cheaper green coffee. However, our allegiance is to quality, so our aim is to buy specialty coffee with minimal defects and the best possible potential. The coffee that has the best potential for flavor is the one with the fewest defects.
More on how we source our green coffee: Sourcing Our Coffee Responsibly
From the horse’s mouth, here are the protocols that the Specialty Coffee Association has defined on grading green coffee: http://www.scaa.org/?page=resources&d=green-coffee-protocols