The Decaf Processes
Green coffee is decaffeinated before roasting. This process changes the color of the green coffee: it varies from light brown (Natural and CO-2) to green-brown (MC and Swiss Water Process -SWP- decafs). There is another decaf we list as WP, Water Process, which is a water filtration method similar to Swiss Water, but performed at a plant in Mexico.
The arrival of decafs always follows the main crop of a coffee by some months, since the coffee needs to be shipped to the decaffeination plant. Oddly, there are only a few such plants in the world, so decaf coffee has to travel a long way usually from origin, to plant and then to the buyer's country. This adds to the cost too, so decafs are often a bit pricier.
Decaf coffees might roast faster than non-decaf coffees. Part of the differences in how a decaf roasts is due to the physical changes the coffee has experienced in the decaffeination process. But in an air roaster it is also affected by the smooth surface of the bean, which allows more air to flow around the coffee without transferring the roaster heat to the bean. This smooth appearance is due to the fact that decaffeination removes much of the thin chaff silverskin from the outside of the coffee. As a plus, decaf produces little chaff that will collect in your roaster's chaff collector.
Because of the darker color of decaf coffees, it is difficult to roast decaf by judging the color. It's best to pay attention to the sound of the cracks and the roast aromas. It takes a few roasts to understand these sights and smells, but its a fun process and even if the coffee comes out a bit too light or too dark, it will still be freshly home roasted! And that beats most store-bought coffee any day!
Decafs can have a lower 1st and 2nd crack temperature, and can progress faster between the cracks. You can also see oils emerge a few days after roasting a decaf despite the fact that you did not reach 2nd crack (the usual reason you would see oils emerge). This is because the bean structure of a decaf is more fragile after the process, and the cell walls in the coffee tend to rupture at a lower temperature, allowing oils to migrate to the surface. As with all coffees, oils stale when exposed to oxygen, so it is preferred that your coffee is not oily on the surface, but for darker roasts and decafs it is unavoidable.
Good news or scary as heck? Geneticists are working on a plant that will grow coffee with no caffeine content, thus needing no processing to remove the caffeine. Is this good? It means no factory process to remove caffeine. It also could mean contamination between natural unmodified trees and modified ones. Coffee is very complex in terms of it's chemical makeup. it has over 800 compounds contributing to the flavor, more than any other beverage. Can you turn off one genetic attribute and not affect others? We shall see the results from the current research work being conducted in Hawaii.