The roasting of green coffee beans is a magical process that is akin to alchemy. Many factors will play into what will become an excellent (or poor) cup of coffee. These factors include the type and quality of the bean, the roasting process, the freshness of the roast, the water used to brew the coffee, and the brewing method. At Z-Best Coffee we only roast coffee after it has been ordered and we ship it immediately to ensure that our customers always receive fresh roasted coffee beans.
Let’s discuss the important factor of the roasting of the beans. A master roaster can take an average bean and produce a very good cup of coffee. A less than average roaster can take a world class bean and produce a cup of coffee with no redeeming qualities, to say the least. In other words, roasting is a subtle art.
When it comes to the hardware, there are two main types of roasters. (Note: The term roaster refers to the machine used to roast the beans and it also is used to refer to the person who operates the roasting machine.) The newer type of roaster is known as the air roaster, which works on the same principle as a hot air popcorn popper or hair dryer. It uses an electric heating element as a heat source. The older and still most common type of roasting machine is the gas-fired barrel roaster. A fairly simple yet heavy machine, it consists of a metal drum inside a metal jacket which rotates like a clothes dryer. The inner drum is perforated with tiny holes to let heat in and allow gasses and smoke, which are formed during the roasting process, to escape. The gas burners are located under the rotating barrel, which heats up to approximately 425 to 450 degrees Fahrenheit.
At Z-Best Coffee, we employ the traditional gas-fired barrel roasting method and we feel that this time-honored tradition yields the finest end product.
The green coffee beans are first poured into a funnel-shaped opening at the top of the machine. During the roasting process, the coffee beans first through off 11% or so of moisture that is trapped in the raw coffee beans. The coffee beans are at this point a straw yellow color. Now the actual roasting begins. The coffee beans go through the stages of light cinnamon roast and continue to darken until the roaster (human) determines that the proper roast has been achieved for this particular type of coffee bean or what the customer has requested
All green coffee beans are high in chlorogenic acid (7%) which by itself is unpleasantly astringent. Through the roasting progresses much of the chlorogenic acid disappears and other tasty acids form. These include acetic acid, (found in vinegar) citric acid, (as in citrus fruits) and malic acid (as in apples, grapes and certain wines). As the carbohydrates in the green coffee beans are heated, toasty sweet flavors develop.
Acidity gives a cup much of its complexity. If there is not enough of it, coffee looses its life and sparkle. A light to medium roast, which shows off acids, will many times be light in body because it lacks many of the caramelized sugars that give body (and mouth feel) to a darker roast.
After the perfect roast has been achieved, the coffee beans are dumped out of a crescent-moon shaped opening at the bottom front of the machine. As the coffee beans spill into the cooling tray, they make a swooshing sound. The coffee beans are then cooled with a rotating paddle and air cooled by a fan that sucks air through the beans through small holes at the base of the cooling chamber.
To cool the coffee beans, some roasters use a method called quenching which entails spraying the hot beans with a mist of water to hasten the cooling process. However, we at Z-Best feel this is a risky method because just a little bit too much water can damage the coffee beans and compromise flavor. Roasting in small quantities allows for quicker cooling, which also contributes to a better quality finished product.
A by-product of roasting is a paper-thin shell known as chaff. Chaff is undesirable in the beans because it adds bitterness. We at Z-Best manage to cast off the chaff by manually pouring the cooling beans from one container into another in front of a fan. This hastens the cooling process and provides a cleaner tasting cup of coffee.
After a few minutes of cooling, the beans are then ready for packing and shipping. Green coffee beans can last many years if stored properly. However, once beans have been roasted, they have a relatively short shelf life before the oils begin to break down and rancidity develops. Air, moisture and sunlight are enemies of roasted coffee. Besides tasting better, fresh coffee is healthier.